A155576 Intersection of A000404 and A155716: N = a^2 + b^2 = c^2 + 6d^2 for some positive integers a,b,c,d.

10, 25, 40, 58, 73, 90, 97, 100, 106, 145, 160, 193, 202, 225, 232, 241, 250, 265, 292, 298, 313, 337, 346, 360, 388, 394, 400, 409, 424, 433, 457, 490, 505, 522, 538, 577, 580, 586, 601, 625, 634, 640, 657, 673, 730, 745, 769, 772, 778, 808, 810, 841, 865

Offset

1,1

Comments

Subsequence of A155566 (where a,b,c,d may be zero).

Links

Table of n, a(n) for n=1..53.

Prog

(PARI) isA155576(n, /* optional 2nd arg allows us to get other sequences */c=[6, 1]) = { for(i=1, #c, for(b=1, sqrtint((n-1)\c[i]), issquare(n-c[i]*b^2) & next(2)); return); 1}
for( n=1, 999, isA155576(n) & print1(n", "))

Crossrefs

Cf. A000404, A154777, A092572, A097268, A154778, A155716, ...

Sequence in context: A003344 A345853 A047721 * A269457 A043123 A043903

Adjacent sequences: A155573 A155574 A155575 * A155577 A155578 A155579

Keyword

easy,nonn

Author

M. F. Hasler, Jan 25 2009

Status

approved