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 A130830 Irregular triangle read by rows: row(1) = [1,2,3]; thereafter row(n+1) is the tensor square of row(n). 1
 1, 2, 3, 1, 2, 3, 2, 4, 6, 3, 6, 9, 1, 2, 3, 2, 4, 6, 3, 6, 9, 2, 4, 6, 4, 8, 12, 6, 12, 18, 3, 6, 9, 6, 12, 18, 9, 18, 27, 2, 4, 6, 4, 8, 12, 6, 12, 18, 4, 8, 12, 8, 16, 24, 12, 24, 36, 6, 12, 18, 12, 24, 36, 18, 36, 54, 3, 6, 9, 6, 12, 18, 9, 18, 27, 6, 12, 18, 12, 24, 36, 18, 36, 54, 9, 18, 27 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Self-similar recursion based on number set {1,2,3}. Row lengths are A011764. LINKS FORMULA It appears that a(n) = A006047(n-12) for n >= 13. - Michel Marcus, Oct 24 2017 EXAMPLE Triangle begins: {1, 2, 3}, {1, 2, 3, 2, 4, 6, 3, 6, 9}, {1, 2, 3, 2, 4, 6, 3, 6, 9, 2, 4, 6, 4, 8, 12, 6, 12, 18, 3, 6, 9, 6, 12, 18, 9, 18, 27, 2, 4, 6, 4, 8, 12, 6, 12, 18, 4, 8, 12, 8, 16, 24, 12, 24, 36, 6, 12, 18, 12, 24, 36, 18, 36, 54, 3, 6, 9, 6, 12, 18, 9, 18, 27, 6, 12, 18, 12, 24, 36, 18, 36, 54, 9, 18, 27, 18, 36, 54, 27, 54, 81}, ... MATHEMATICA a[1] = {1, 2, 3}; a[2] = {1, 2, 3, 2, 4, 6, 3, 6, 9}; a[n_] := a[n] = Flatten[Table[a[n - 1][[m]]*a[n - 1], {m, 1, Length[a[n - 1]]}]]; w = Table[a[n], {n, 1, 3}]; Flatten[w] CROSSREFS Cf. A011764, A115245, A130831. Sequence in context: A105933 A105315 A328912 * A131989 A305390 A344310 Adjacent sequences:  A130827 A130828 A130829 * A130831 A130832 A130833 KEYWORD nonn,tabf AUTHOR Roger L. Bagula, Aug 20 2007 EXTENSIONS Edited by N. J. A. Sloane, Jun 07 2008 STATUS approved

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Last modified December 3 22:32 EST 2021. Contains 349468 sequences. (Running on oeis4.)