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A163077 Numbers k such that k$ + 1 is prime. Here '$' denotes the swinging factorial function (A056040). 3
0, 1, 2, 3, 4, 5, 8, 9, 14, 15, 24, 27, 31, 38, 44, 45, 49, 67, 76, 92, 99, 119, 124, 133, 136, 139, 144, 168, 171, 185, 265, 291, 332, 368, 428, 501, 631, 680, 689, 696, 765, 789, 890, 1034, 1233, 1384, 1517, 1615, 1634, 1809, 2632, 2762, 3925, 4419, 5108, 5426 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
Peter Luschny, Swinging Primes.
EXAMPLE
0$ + 1 = 1 + 1 = 2 is prime, so 0 is in the sequence.
MAPLE
a := proc(n) select(x -> isprime(A056040(x)+1), [$0..n]) end:
MATHEMATICA
fQ[n_] := PrimeQ[1 + 2^(n - Mod[n, 2])*Product[k^((-1)^(k + 1)), {k, n}]]; Select[ Range[0, 8660], fQ] (* Robert G. Wilson v, Aug 09 2010 *)
PROG
(PARI) is(k) = ispseudoprime(1+k!/(k\2)!^2); \\ Jinyuan Wang, Mar 22 2020
CROSSREFS
Sequence in context: A329203 A054181 A329563 * A204810 A240080 A194714
KEYWORD
nonn
AUTHOR
Peter Luschny, Jul 21 2009
EXTENSIONS
a(45)-a(56) from Robert G. Wilson v, Aug 09 2010
STATUS
approved

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Last modified March 3 15:08 EST 2024. Contains 370512 sequences. (Running on oeis4.)