A328223 Numbers k such that both k and k+4 are sums of two squares.
0, 1, 4, 5, 9, 13, 16, 25, 32, 36, 37, 41, 45, 49, 61, 64, 68, 81, 85, 97, 100, 109, 113, 117, 121, 144, 145, 149, 153, 160, 169, 181, 193, 196, 208, 221, 225, 229, 241, 256, 257, 261, 265, 277, 288, 289, 292, 313, 320, 324, 333, 349, 356, 361, 365, 369, 373, 388, 397, 400
Offset: 1
Keywords
Programs
-
Magma
[k: k in [0..400] | NormEquation(1, k) eq true and NormEquation(1, k+4) eq true]; // Marius A. Burtea, Oct 08 2019
-
Mathematica
ok[n_] := AllTrue[{0, 4}, SquaresR[2, # + n] > 0 &]; Select[Range[0, 400], ok] (* Giovanni Resta, Oct 08 2019 *)