A155577 -id:A155577 - cp's OEIS frontend

A155567 Intersection of A002479 and A020669 : N = a^2 + 2b^2 = c^2 + 5d^2 for some integers a,b,c,d.

0, 1, 4, 6, 9, 16, 24, 25, 36, 41, 49, 54, 64, 81, 86, 89, 96, 100, 121, 129, 134, 144, 150, 164, 166, 169, 196, 201, 214, 216, 225, 241, 246, 249, 256, 281, 289, 294, 321, 324, 326, 344, 356, 361, 369, 384, 400, 401, 409, 441, 449, 454, 484, 486, 489, 516, 521

Offset: 1

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M. F. Hasler, Jan 25 2009

easy
nonn

Contains A155577 as a subsequence (obtained by restricting a,b,c,d to be nonzero). Also contains A000290 (squares) as subsequence.

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

isA155567(n,/* use optional 2nd arg to get other analogous sequences */c=[5,2]) = { for(i=1,#c, for(b=0,sqrtint(n\c[i]), issquare(n-c[i]*b^2) & next(2)); return);1}
for( n=1,600, isA155567(n) & print1(n","))

cp's OEIS Frontend

A155567 Intersection of A002479 and A020669 : N = a^2 + 2b^2 = c^2 + 5d^2 for some integers a,b,c,d.

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