A214512 Least number having n orderless representations as p^2 + q^2 + r^2, where p, q, and r are primes.

12, 219, 363, 699, 1179, 2019, 2259, 3891, 4059, 6459, 5379, 10899, 13179, 10659, 12579, 21819, 20979, 26859, 34419, 38379, 41019, 61299, 39459, 41811, 82131, 50379, 77451, 71379, 141099, 85491, 103971, 74571, 180411, 108339, 179739, 161139, 126819, 225099

Offset

1,1

Links

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

Mathematica

nn = 10^6; ps = Prime[Range[PrimePi[Sqrt[nn]]]]; t = Flatten[Table[ps[[i]]^2 + ps[[j]]^2 + ps[[k]]^2, {i, Length[ps]}, {j, i, Length[ps]}, {k, j, 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. A025414, A025415, A214511, A214513.

Sequence in context: A374892 A087585 A297503 * A372171 A220068 A247745

Adjacent sequences: A214509 A214510 A214511 * A214513 A214514 A214515

Keyword

nonn

Author

T. D. Noe, Jul 29 2012

Status

approved