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A076199
a(n) equals the least s>0 such that n!! + s^2 is prime.
0
1, 1, 2, 3, 2, 5, 2, 5, 8, 7, 2, 19, 4, 17, 58, 11, 2, 17, 8, 31, 32, 17, 8, 13, 4, 23, 4, 23, 2, 53, 86, 37, 32, 23, 164, 79, 86, 23, 2, 229, 94, 89, 2, 89, 4, 83, 4, 149, 134, 31, 8, 83, 4, 53, 206, 227, 206, 283, 64, 43, 274, 37, 128, 263, 214, 163, 146, 167, 326, 157, 178
OFFSET
1,3
MATHEMATICA
sp[n_]:=Module[{np=NextPrime[n]}, While[!IntegerQ[Sqrt[np-n]], np = NextPrime[ np]]; Sqrt[np-n]]; sp/@(Range[80]!!) (* Harvey P. Dale, Aug 04 2014 *)
CROSSREFS
Cf. A057019.
Sequence in context: A073893 A099552 A252749 * A318057 A136096 A284694
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 02 2002
STATUS
approved