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 A082657 Integers expressible as the sum of a square and a triangular number in just one way. 4
 1, 2, 3, 4, 5, 6, 11, 12, 14, 16, 17, 21, 24, 25, 29, 30, 32, 35, 36, 39, 42, 44, 49, 50, 51, 53, 54, 56, 57, 65, 66, 71, 72, 74, 75, 77, 78, 80, 81, 84, 95, 96, 101, 104, 105, 107, 110, 116, 117, 119, 120, 122, 126, 128, 129, 131, 137, 141, 149, 150, 152, 153, 156, 161 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS It is assumed here that 0 is a square but not a triangular number. - Amiram Eldar, Dec 08 2019 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 MATHEMATICA aQ[n_] := Length @ Solve[x^2 + y (y + 1)/2 == n && x >= 0 && y > 0, {x, y}, Integers] == 1; Select[Range[161], aQ] (* Amiram Eldar, Dec 08 2019 *) CROSSREFS Cf. A000217, A000290, A082658, A082659, A082660. Sequence in context: A032984 A108379 A348256 * A108378 A084588 A309548 Adjacent sequences: A082654 A082655 A082656 * A082658 A082659 A082660 KEYWORD nonn AUTHOR Jason Earls, May 17 2003 STATUS approved

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Last modified March 26 11:03 EDT 2023. Contains 361540 sequences. (Running on oeis4.)