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A155576 Intersection of A000404 and A155716: N = a^2 + b^2 = c^2 + 6d^2 for some positive integers a,b,c,d. 1

%I #4 Jul 14 2012 11:32:23

%S 10,25,40,58,73,90,97,100,106,145,160,193,202,225,232,241,250,265,292,

%T 298,313,337,346,360,388,394,400,409,424,433,457,490,505,522,538,577,

%U 580,586,601,625,634,640,657,673,730,745,769,772,778,808,810,841,865

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

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

%o (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}

%o for( n=1,999, isA155576(n) & print1(n","))

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

%K easy,nonn

%O 1,1

%A _M. F. Hasler_, Jan 25 2009

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Last modified April 24 07:01 EDT 2024. Contains 371920 sequences. (Running on oeis4.)