A155569 Intersection of A002479 inter A002481: N = a^2 + 2b^2 = c^2 + 6d^2 for some integers a,b,c,d.

0, 1, 4, 6, 9, 16, 22, 24, 25, 33, 36, 49, 54, 64, 73, 81, 88, 96, 97, 100, 118, 121, 132, 144, 150, 166, 169, 177, 193, 196, 198, 214, 216, 225, 241, 249, 256, 262, 289, 292, 294, 297, 313, 321, 324, 337, 352, 358, 361, 384, 388, 393, 400, 409, 433, 438, 441

Offset: 1

Author

M. F. Hasler, Jan 25 2009

Keywords

• easy
• nonn

Comments

Contains A155709 as a subsequence (obtained by restricting a,b,c,d to be nonzero). Also contains A000290 (squares) as subsequence.

Crossrefs

Cf. A001481, A002479, A003136, A002481, A020668 ff.

Programs

PARI

isA155569(n,/* use optional 2nd arg to get other analogous sequences */c=[6,2]) = { for(i=1,#c, for(b=0,sqrtint(n\c[i]), issquare(n-c[i]*b^2) & next(2)); return);1}
for( n=0,500, isA155569(n) & print1(n","))