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 A081741 Numbers k that divide A005554(k) (the sum of consecutive Motzkin numbers). 1
 1, 2, 3, 6, 9, 18, 27, 54, 81, 102, 126, 162, 189, 243, 369, 486, 567, 729, 1071, 1134, 1323, 1458, 1462, 1539, 2187, 2538, 2889, 3213, 4374, 4617, 6561, 7749, 8262, 8667, 13122, 14238, 15498, 19683, 24786, 27702, 28994, 32319, 34263, 39366, 40838 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS All the powers of 3 (A000244) are in the sequence. LINKS Amiram Eldar, Table of n, a(n) for n = 1..165 MATHEMATICA s = {1, 2}; k1 = 1; k2 = 2; Do[k3 = (2*n*k2 + (3*n - 9)*k1)/(n + 1); If[Divisible[k3, n], AppendTo[s, n]]; k1 = k2; k2 = k3, {n, 3, 42000}]; s (* Amiram Eldar, Jun 28 2022 *) CROSSREFS Cf. A000244, A001006, A005554. Sequence in context: A206100 A178940 A018264 * A035522 A018311 A018481 Adjacent sequences: A081738 A081739 A081740 * A081742 A081743 A081744 KEYWORD nonn AUTHOR Benoit Cloitre, Apr 07 2003 STATUS approved

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Last modified October 2 20:55 EDT 2023. Contains 365840 sequences. (Running on oeis4.)