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Revision History for A073607

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Smallest of three consecutive integers divisible by three consecutive primes respectively.
(history; published version)
#9 by Peter Luschny at Tue Mar 23 05:20:11 EDT 2021
STATUS

proposed

approved

#8 by Michel Marcus at Tue Mar 23 04:52:29 EDT 2021
STATUS

editing

proposed

#7 by Michel Marcus at Tue Mar 23 04:52:26 EDT 2021
EXAMPLE

20 is a term as 20,21 and 22 are divisible by 5,7 and 11 respectively. 114 is a term as 114, 115 and 116 are divisible by 19, 23 and 29 respectively.

114 is a term as 114, 115 and 116 are divisible by 19, 23 and 29 respectively.

STATUS

proposed

editing

#6 by Amiram Eldar at Tue Mar 23 04:25:34 EDT 2021
STATUS

editing

proposed

#5 by Amiram Eldar at Tue Mar 23 04:09:42 EDT 2021
COMMENTS

The sequence is infinite as 30k 30*k + 8 is a member for all k. What is the longest string of consecutive integers?

LINKS

Amiram Eldar, <a href="/A073607/b073607.txt">Table of n, a(n) for n = 1..10000</a>

CROSSREFS
STATUS

approved

editing

#4 by N. J. A. Sloane at Thu Dec 05 19:55:21 EST 2013
AUTHOR

_Amarnath Murthy (amarnath_murthy(AT)yahoo.com), _, Aug 04 2002

Discussion
Thu Dec 05
19:55
OEIS Server: https://oeis.org/edit/global/2075
#3 by Russ Cox at Fri Mar 30 17:30:48 EDT 2012
EXTENSIONS

Edited, corrected and extended by _Robert G. Wilson v (rgwv(AT)rgwv.com), _, Aug 06 2002

Discussion
Fri Mar 30
17:30
OEIS Server: https://oeis.org/edit/global/156
#2 by N. J. A. Sloane at Tue Jan 24 03:00:00 EST 2006
MATHEMATICA

f[ n_Integer ] := Flatten[ Table[ #1 ] & @@@ FactorInteger[ n ] ]; NextPrim[ n_ ] := Block[ {k = n + 1}, While[ !PrimeQ[ k ], k++ ]; k ]; Do[ p = f[ n ]; l = Length[ p ]; t = Table[ n + i, {i, 0, 2} ]; k = 1; While[ k < l + 1 && Union[ Mod[ t, NestList[ NextPrim, p[ [ k ] ], 2 ] ] ] != {0}, k++ ]; If[ k < l + 1, Print[ n ] ], {n, 2, 1117} ]

KEYWORD

nonn,new

nonn

#1 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003
NAME

Smallest of three consecutive integers divisible by three consecutive primes respectively.

DATA

8, 20, 38, 54, 68, 98, 114, 128, 158, 159, 169, 188, 218, 248, 264, 278, 308, 338, 368, 369, 398, 405, 428, 458, 474, 488, 518, 548, 578, 579, 608, 638, 668, 684, 698, 728, 758, 788, 789, 790, 791, 818, 848, 878, 894, 908, 938, 968, 998, 999, 1028, 1058

OFFSET

1,1

COMMENTS

The sequence is infinite as 30k + 8 is a member for all k. What is the longest string of consecutive integers?

EXAMPLE

20 is a term as 20,21 and 22 are divisible by 5,7 and 11 respectively. 114 is a term as 114, 115 and 116 are divisible by 19, 23 and 29 respectively.

MATHEMATICA

f[ n_Integer ] := Flatten[ Table[ #1 ] & @@@ FactorInteger[ n ] ]; NextPrim[ n_ ] := Block[ {k = n + 1}, While[ !PrimeQ[ k ], k++ ]; k ]; Do[ p = f[ n ]; l = Length[ p ]; t = Table[ n + i, {i, 0, 2} ]; k = 1; While[ k < l + 1 && Union[ Mod[ t, NestList[ NextPrim, p[ [ k ] ], 2 ] ] ] != {0}, k++ ]; If[ k < l + 1, Print[ n ] ], {n, 2, 1117} ]

CROSSREFS
KEYWORD

nonn

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 04 2002

EXTENSIONS

Edited, corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 06 2002

STATUS

approved