The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A216288

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Showing entries 1-10 | older changes

A216288

Prime-free decades such that the next decade is also prime-free.
(history; published version)

#21 by Charles R Greathouse IV at Thu Sep 08 08:46:03 EDT 2022

PROG

(MAGMAMagma) /* After the Greathouse's comment: */ [n: n in [0..1200] | forall{10*n+i: i in [1, 3, 7, 9, 11, 13, 17, 19] | not IsPrime(10*n+i)}]; // Bruno Berselli, Sep 14 2012

Discussion

Thu Sep 08

08:46

OEIS Server: https://oeis.org/edit/global/2944

#20 by Charles R Greathouse IV at Mon May 13 01:54:22 EDT 2013

LINKS

_Charles R Greathouse IV_, , <a href="/A216288/b216288.txt">Table of n, a(n) for n = 1..10000</a>

Discussion

Mon May 13

01:54

OEIS Server: https://oeis.org/edit/global/1915

#19 by Charles R Greathouse IV at Mon May 13 01:50:07 EDT 2013

LINKS

_Charles R Greathouse IV, _, <a href="/A216288/b216288.txt">Table of n, a(n) for n = 1..10000</a>

Discussion

Mon May 13

01:50

OEIS Server: https://oeis.org/edit/global/1914

#18 by T. D. Noe at Sat Dec 08 12:24:23 EST 2012

STATUS

proposed

approved

#17 by V. Raman at Sat Dec 08 04:11:18 EST 2012

STATUS

editing

proposed

#16 by V. Raman at Sat Dec 08 04:09:46 EST 2012

FORMULA

a(n) = A219998(n) - 1. - V. Raman, Dec 08 2012

PROG

(PARI) for(i=2, 1200, if(isprime(10*i+1)==0&&isprime(10*i+3)==0&&isprime(10*i+7)==0&&isprime(10*i+9)==0&&isprime(10*i+11)==0&&isprime(10*i+13)==0&&isprime(10*i+17)==0&&isprime(10*i+19)==0, print1(i", "))) /* V. Raman, Dec 08 2012 */

CROSSREFS

Cf. A219998 (upper decade).

STATUS

approved

editing

#15 by T. D. Noe at Fri Dec 07 19:48:31 EST 2012

STATUS

editing

approved

#14 by T. D. Noe at Fri Dec 07 19:48:26 EST 2012

KEYWORD

nonn,base

STATUS

approved

editing

#13 by Bruno Berselli at Fri Sep 14 04:27:39 EDT 2012

STATUS

editing

approved

#12 by Bruno Berselli at Fri Sep 14 04:26:56 EDT 2012

PROG

(MAGMA) /* After the Greathouse's comment: */ [n: n in [0..1200] | forall{10*n+i: i in [1, 3, 7, 9, 11, 13, 17, 19] | not IsPrime(10*n+i)}]; // Bruno Berselli, Sep 14 2012

STATUS

approved

editing