A214513 Least number having n orderless representations as p^2 + q^2 + r^2 + s^2, where p, q, r, and s are primes.

16, 148, 196, 436, 388, 628, 868, 988, 1228, 1468, 1708, 2212, 2068, 2860, 2620, 2380, 3220, 3388, 3700, 4108, 3940, 4180, 5260, 4228, 5068, 4900, 5500, 6220, 6340, 7780, 5908, 5740, 6580, 7540, 8260, 7420, 8860, 9340, 11260, 10708, 9940, 9100, 10180, 12820

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Mathematica

nn = 10^5; 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 &]; t2 = Sort[Tally[t]]; u = Union[Transpose[t2][[2]]]; d = Complement[Range[u[[-1]]], u]; If[d == {}, nLim = u[[-1]], nLim = d[[1]]-1]; t3 = Table[Select[t2, #[[2]] == n &, 1][[1]], {n, nLim}]; Transpose[t3][[1]]

Crossrefs

Cf. A025416, A025417, A214511, A214512.

Sequence in context: A126537 A252818 A232957 * A254952 A178259 A269137

Adjacent sequences: A214510 A214511 A214512 * A214514 A214515 A214516

Keyword

nonn

Author

T. D. Noe, Jul 29 2012

Status

approved