A288405 Primes of the form k!2+4, where k!2 is the double factorial number (A006852).

5, 7, 19, 109, 10399, 34459429, 6190283353629379, 319830986772877770815629, 563862029680583509947946879, 174865344543353986303948473285124243127671456831640629, 2987435000850314871976096554696085799164511452611632783323554397412109379

Offset

1,1

Links

Robert Price, Table of n, a(n) for n = 1..11

Henri& Renaud Lifchitz, PRP Records.Search for n!2+4.

Joe McLean, Interesting Sources of Probable Primes

OpenPFGW Project, Primality Tester

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 2] + 4, {i, 0, 100}], PrimeQ[#]&]

Crossrefs

Cf. A076186.

Sequence in context: A171131 A096636 A101588 * A280150 A062654 A231865

Adjacent sequences: A288402 A288403 A288404 * A288406 A288407 A288408

Keyword

nonn

Author

Robert Price, Jun 08 2017

Status

approved