The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A105050 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A105050

a(0)=2, a(n) is the smallest prime of the form a(n-1)*k^2 + 1.
(history; published version)

#7 by Alois P. Heinz at Mon Aug 02 12:29:38 EDT 2021

STATUS

reviewed

approved

#6 by Hugo Pfoertner at Mon Aug 02 12:14:15 EDT 2021

STATUS

proposed

reviewed

#5 by Jinyuan Wang at Mon Aug 02 08:57:48 EDT 2021

STATUS

editing

proposed

#4 by Jinyuan Wang at Mon Aug 02 08:57:32 EDT 2021

EXAMPLE

a(5) = 30529 = 53*24^2 + 1 is the smallest prime of the form 53*k^2 + 1.

#3 by Jinyuan Wang at Mon Aug 02 08:57:08 EDT 2021

NAME

a(0)=2, a(n) is the smallest prime of the form a(n-1)*k^2 + 1.

DATA

2, 3, 13, 53, 30529, 122117, 17584849, 70339397, 22789964629, 11030342880437, 9927308592393301, 91490075987496662017, 23421459452799145476353, 918214896387537699254943013, 528891780319221714770847175489, 8665362928750128574805560123211777, 311953065435004628693000164435623973

EXAMPLE

a(5) = 30529 = 53*24^2 + 1 is the smallest prime of the form 53k53*k^2+1.

PROG

(PARI) lista(nn) = my(k, p=2); print1(p); for(n=1, nn, k=1; while(!isprime(p*k^2+1), k++); print1(", ", p=p*k^2+1)); \\ Jinyuan Wang, Aug 02 2021

CROSSREFS

Cf. A061092, A093490.

EXTENSIONS

a(15)-a(16) from Jinyuan Wang, Aug 02 2021

STATUS

approved

editing

#2 by Russ Cox at Sat Mar 31 21:08:20 EDT 2012

AUTHOR

_John L. Drost (drost(AT)marshall.com), _, Apr 04 2005

Discussion

Sat Mar 31

21:08

OEIS Server: https://oeis.org/edit/global/1499

#1 by N. J. A. Sloane at Sat Apr 09 03:00:00 EDT 2005

NAME

a(0)=2, a(n) is the smallest prime of the form a(n-1)*k^2+1.

DATA

OFFSET

0,1

EXAMPLE

a(5)=30529=53*24^2+1 is the smallest prime of the form 53k^2+1

KEYWORD

nonn,new

AUTHOR

John L. Drost (drost(AT)marshall.com), Apr 04 2005

STATUS

approved