The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A264776

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A264776

a(n) is least number > 0 such that the concatenation of a(1) ... a(n) is pentagonal: (3n^2 - n)/2.
(history; published version)

#21 by Jon E. Schoenfield at Sun Jul 14 22:24:42 EDT 2019

STATUS

editing

approved

#20 by Jon E. Schoenfield at Sun Jul 14 22:23:40 EDT 2019

COMMENTS

It appears that a(n) = ceiling((a(n-1) + 5/12)*10^(7*2^(n-6))) for n >= 7. - Jon E. Schoenfield, Nov 24 2015

STATUS

approved

editing

#19 by N. J. A. Sloane at Wed Nov 25 20:49:44 EST 2015

STATUS

proposed

approved

#18 by Michel Marcus at Wed Nov 25 01:01:45 EST 2015

STATUS

editing

proposed

#17 by Michel Marcus at Wed Nov 25 01:01:39 EST 2015

CROSSREFS

Cf. A264738, A000326, A264738.

STATUS

proposed

editing

#16 by Jon E. Schoenfield at Tue Nov 24 23:12:25 EST 2015

STATUS

editing

proposed

#15 by Jon E. Schoenfield at Tue Nov 24 23:12:19 EST 2015

NAME

a(n) is least number > 0 such that the concatenation of a(1) ... a(n) is pentagonal: (3n^2 - n)/2.

#14 by Jon E. Schoenfield at Tue Nov 24 23:11:45 EST 2015

COMMENTS

It appears that a(n) = ceiling((a(n-1) + 5/12)*10^(7*2^(n-6))) for n>=7. - Jon E. Schoenfield, Nov 24 2015

EXTENSIONS

a(6)-a(8) from Jon E. Schoenfield, Nov 24 2015

#13 by Jon E. Schoenfield at Tue Nov 24 22:56:09 EST 2015

DATA

1, 2, 47, 160, 6070026, 47418729166667, 4741872916666741666666666667, 47418729166667416666666666674166666666666666666666666667

STATUS

proposed

editing

#12 by Anders Hellström at Tue Nov 24 13:06:22 EST 2015

STATUS

editing

proposed