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A155570
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Intersection of A003136 and A020669: N = a^2 + 3b^2 = c^2 + 5d^2 for some integers a,b,c,d.
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1
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0, 1, 4, 9, 16, 21, 25, 36, 49, 61, 64, 81, 84, 100, 109, 121, 129, 144, 169, 181, 189, 196, 201, 225, 229, 241, 244, 256, 289, 301, 309, 324, 336, 349, 361, 381, 400, 409, 421, 436, 441, 469, 484, 489, 516, 525, 529, 541, 549, 576, 601, 625, 661, 669, 676, 709
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OFFSET
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1,3
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COMMENTS
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Contains A155710 as a subsequence (obtained by restricting a,b,c,d to be nonzero). Also contains A000290 (squares) as subsequence.
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LINKS
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PROG
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(PARI) isA155570(n, /* use optional 2nd arg to get other analogous sequences */c=[5, 3]) = { for(i=1, #c, for(b=0, sqrtint(n\c[i]), issquare(n-c[i]*b^2) & next(2)); return); 1}
for( n=0, 800, isA155570(n) & print1(n", "))
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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