OFFSET
5,1
COMMENTS
a(n) = 0 for n: 44, 63, 71, 80, 89, 95, 97, 108, 118, 122, 132, 141, 150, etc. Robert G. Wilson v, Feb 15 2017
EXAMPLE
Let n=9, prime(9)=23. If m=3, then odd part of (23^2 - 5^2)/24 is 21, while if m=4, then odd part of (23^2 - 7^2)/24 is 5 which is prime. So a(9)=4.
MATHEMATICA
f[n_] := Block[{m = 3, p = Prime[n]^2}, While[q = (p - Prime[m]^2)/3; m < n && ! PrimeQ[q/2^IntegerExponent[q, 2]], m++]; If[m < n, m, 0]]; Array[f, 73, 5] (* Robert G. Wilson v, Feb 15 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Feb 15 2017
EXTENSIONS
More terms from Peter J. C. Moses, Feb 15 2017
STATUS
approved