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A288405 Primes of the form k!2+4, where k!2 is the double factorial number (A006852). 1
5, 7, 19, 109, 10399, 34459429, 6190283353629379, 319830986772877770815629, 563862029680583509947946879, 174865344543353986303948473285124243127671456831640629, 2987435000850314871976096554696085799164511452611632783323554397412109379 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Henri& Renaud Lifchitz, PRP Records.Search for n!2+4.
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
KEYWORD
nonn
AUTHOR
Robert Price, Jun 08 2017
STATUS
approved

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)