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 A020675 Numbers of form 2 x^2 + 7 y^2. 1
 0, 2, 7, 8, 9, 15, 18, 25, 28, 30, 32, 36, 39, 46, 50, 57, 60, 63, 65, 71, 72, 78, 79, 81, 95, 98, 100, 105, 112, 113, 114, 120, 126, 128, 130, 135, 144, 156, 161, 162, 169, 175, 177, 183, 184, 190, 191, 193, 200, 207, 210, 225, 228, 240, 242, 247, 249, 252, 254, 260, 263 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..61. N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references) MATHEMATICA With[{nn=80}, Take[Union[2#[[1]]+7#[[2]]&/@Tuples[Range[0, nn/4]^2, 2]], nn]] (* Harvey P. Dale, Jul 17 2015 *) CROSSREFS Sequence in context: A179772 A047354 A037455 * A317303 A045980 A104339 Adjacent sequences: A020672 A020673 A020674 * A020676 A020677 A020678 KEYWORD easy,nonn AUTHOR David W. Wilson STATUS approved

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Last modified June 17 15:45 EDT 2024. Contains 373458 sequences. (Running on oeis4.)