The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A139204 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A139204

Numbers k such that (k!-9)/9 is prime.
(history; published version)

#21 by N. J. A. Sloane at Wed Mar 29 19:46:20 EDT 2017

STATUS

proposed

approved

#20 by Robert Price at Wed Mar 29 18:15:08 EDT 2017

STATUS

editing

proposed

#19 by Robert Price at Wed Mar 29 18:14:50 EDT 2017

DATA

6, 15, 17, 18, 21, 27, 29, 30, 37, 47, 50, 64, 125, 251, 602, 611, 1184, 1468, 5570, 10679, 15798, 21237

COMMENTS

a(23) > 25000. - Robert Price, Mar 29 2017

EXTENSIONS

a(20)-a(22) from Robert Price, Mar 29 2017

STATUS

approved

editing

#18 by N. J. A. Sloane at Thu Feb 19 00:08:49 EST 2015

STATUS

proposed

approved

#17 by Serge Batalov at Wed Feb 18 21:07:50 EST 2015

STATUS

editing

proposed

#16 by Serge Batalov at Wed Feb 18 21:07:42 EST 2015

CROSSREFS

Cf. n!/m-1 is a prime: A002982, A082671, A139056, A139199-A139205; n!/m+1 is a prime: A002981, A082672, A089085, A139061, A139058, A139063, A139065, A151913, A137390, A139071 (1<=m<=10).

STATUS

approved

editing

#15 by Giovanni Resta at Fri Mar 28 18:05:39 EDT 2014

STATUS

editing

approved

#14 by Giovanni Resta at Fri Mar 28 18:04:22 EDT 2014

DATA

6, 15, 17, 18, 21, 27, 29, 30, 37, 47, 50, 64, 125, 251, 602, 611, 1184, 1468, 5570

COMMENTS

a(1720) > 100010000. The PFGW program has been used to certify all the terms up to a(19), using a deterministic test which exploits the factorization of a(n) + 1. - _Giovanni Resta_, Mar 28 2014

EXTENSIONS

a(17)-a(19) from Giovanni Resta, Mar 28 2014

STATUS

approved

editing

#13 by Bruno Berselli at Fri Mar 28 11:46:23 EDT 2014

STATUS

reviewed

approved

#12 by Michael B. Porter at Fri Mar 28 11:36:01 EDT 2014

STATUS

proposed

reviewed