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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Primes appear only once.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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 A166632 A116596

Adjacent sequences:  A188109 A188110 A188111 * A188113 A188114 A188115

KEYWORD

nonn,easy

AUTHOR

Zak Seidov, Mar 21 2011

STATUS

approved

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Last modified July 13 13:48 EDT 2020. Contains 335688 sequences. (Running on oeis4.)