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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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%I #3 Jul 14 2012 11:32:23

%S 0,1,4,6,9,16,24,25,36,41,49,54,64,81,86,89,96,100,121,129,134,144,

%T 150,164,166,169,196,201,214,216,225,241,246,249,256,281,289,294,321,

%U 324,326,344,356,361,369,384,400,401,409,441,449,454,484,486,489,516,521

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

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

%o (PARI) 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}

%o for( n=1,600, isA155567(n) & print1(n","))

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

%K easy,nonn

%O 1,3

%A _M. F. Hasler_, Jan 25 2009