A129518 Numbers k > 2 such that k divides (k-2)!! - 1 and (k-3)!! - 1.

3, 7, 47, 59, 79, 83, 103, 107, 127, 139, 191, 199, 211, 251, 263, 283, 307, 331, 367, 379, 383, 431, 467, 479, 499, 503, 547, 587, 599, 607, 631, 643, 659, 727, 743, 811, 823, 827, 839, 859, 863, 883, 887, 907, 971, 991, 1087, 1151, 1163, 1171, 1259, 1283

Offset

1,1

Comments

All terms are primes of the form 4m+3 belonging to A002145. A002145 is the union of this sequence and A129517 (odd primes p such that p divides (p-1)!! - 1).

Odd numbers k > 1 such that k divides (k-1)!! + 1. - Thomas Ordowski, Jul 26 2016

Links

Table of n, a(n) for n=1..52.

Mathematica

Select[Range[3, 2000], IntegerQ[((#-2)!!-1)/# ]&&IntegerQ[((#-3)!!-1)/# ]&]

Crossrefs

Cf. A006882 (double factorials).

Cf. A002145 (primes of form 4k+3).

Cf. A129517 (odd primes p such that p divides (p-1)!! - 1).

Cf. A129516 (numbers k such that k divides (k-1)!! - 1).

Cf. A260298.

Sequence in context: A003758 A231893 A132565 * A007670 A263806 A074714

Adjacent sequences: A129515 A129516 A129517 * A129519 A129520 A129521

Keyword

nonn

Author

Alexander Adamchuk, Apr 18 2007

Status

approved