A214515 Numbers of the form p^2 + q^2 + r^2 + s^2, where p, q, r, and s are primes.

16, 21, 26, 31, 36, 37, 42, 47, 52, 58, 61, 63, 66, 68, 71, 76, 79, 82, 84, 87, 92, 100, 103, 106, 108, 111, 116, 124, 127, 132, 133, 138, 143, 148, 151, 154, 156, 159, 164, 172, 175, 178, 180, 181, 183, 186, 188, 191, 196, 199, 202, 204, 207, 212, 220, 223

Offset

1,1

Links

T. D. Noe, Table of n, a(n) for n = 1..10000

Mathematica

nn = 10^3; ps = Prime[Range[PrimePi[Sqrt[nn]]]]; t = Flatten[Table[ps[[i]]^2 + ps[[j]]^2 + ps[[k]]^2 + ps[[l]]^2, {i, Length[ps]}, {j, i, Length[ps]}, {k, j, Length[ps]}, {l, k, Length[ps]}]]; t = Select[t, # <= nn &]; Union[t]

Crossrefs

Cf. A045636 (two primes), A214514 (three primes).

Sequence in context: A180411 A050436 A038868 * A270783 A330591 A302167

Adjacent sequences: A214512 A214513 A214514 * A214516 A214517 A214518

Keyword

nonn

Author

T. D. Noe, Jul 29 2012

Status

approved