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A188112
Integers of the form x^2+xy+2y^2,with x and y nonnegative, with repetitions.
1
0, 1, 2, 4, 4, 8, 8, 9, 11, 14, 16, 16, 18, 22, 22, 23, 25, 28, 32, 32, 32, 36, 36, 37, 43, 44, 44, 46, 49, 50, 53, 56, 56, 58, 58, 64, 64, 64, 71, 72, 72, 74, 74, 77, 79, 81, 86, 88, 88, 88, 92, 92, 98, 99, 100, 100, 106, 106, 107, 109, 112, 112, 116, 116, 121, 126, 127
OFFSET
1,3
COMMENTS
Primes appear only once.
LINKS
EXAMPLE
{n,x,y}: {0,0,0},...,{4,1,1},{4,2,0},{8,0,2},{8,2,1},...,{11,1,2},{14,3,1}.
MATHEMATICA
f[upto_]:=Module[{max=Floor[Sqrt[upto]], s}, s=Sort[First[#]^2+ Times@@#+2Last[#]^2&/@Tuples[Range[0, max], {2}]]; Select[s, #<=upto&]]; f[150] (* Harvey P. Dale, Mar 28 2011 *)
CROSSREFS
Cf. A106856, primes of the form x^2+xy+2y^2, with x and y nonnegative.
Sequence in context: A207872 A140513 A265322 * A333194 A349131 A366665
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Mar 21 2011
STATUS
approved