A126896 - OEIS

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A126896

Numbers k such that 10*k! + 1 is prime.

9

0, 1, 3, 4, 5, 23, 32, 39, 61, 349, 718, 805, 1025, 1194, 1550, 1774, 3417, 7583

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

a(17) > 2880. - Jinyuan Wang, Feb 05 2020

a(19) > 12000. - Michael S. Branicky, Jul 07 2024

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

k = 4 is a term because 10*4! + 1 = 241 is prime.

PROG

(PARI) is(k) = ispseudoprime(10*k!+1); \\ Jinyuan Wang, Feb 05 2020

CROSSREFS

Cf. A002981, A051915, A076679, A076680, A076681, A076682, A076683, A178488, A180626.

Sequence in context: A372413 A116474 A208807 * A334225 A123957 A370625

Adjacent sequences: A126893 A126894 A126895 * A126897 A126898 A126899

KEYWORD

nonn,more

AUTHOR

Parthasarathy Nambi, May 07 2007

EXTENSIONS

a(15)-a(16) from Jinyuan Wang, Feb 05 2020

a(17) from Michael S. Branicky, Apr 16 2023

a(18) from Michael S. Branicky, Jul 07 2024

STATUS

approved