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

1,3

Comments

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

Links

Table of n, a(n) for n=1..57.

Prog

(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", "))

Crossrefs

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

Sequence in context: A085955 A266346 A181018 * A189484 A155567 A225377

Adjacent sequences: A155566 A155567 A155568 * A155570 A155571 A155572

Keyword

easy,nonn

Author

M. F. Hasler, Jan 25 2009

Status

approved