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 A117267 Difference row triangle of A117189. 1
 1, 1, 2, 2, 3, 5, 4, 6, 9, 14, 7, 11, 17, 26, 40, 13, 20, 31, 48, 74, 114, 24, 37, 57, 88, 136, 210, 324, 44, 68, 105, 162, 250, 386, 596, 920, 81, 125, 193, 298, 460, 710, 1096, 1692, 2612, 149, 230, 355, 548, 846, 1306, 2016, 3112, 4804, 7416 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Take difference rows of A117189 (binomial transform of the tribonacci sequence, A000073); and reorient to a flush left format. LINKS Table of n, a(n) for n=1..55. EXAMPLE Taking difference rows of A117189, we get: 1, 2, 5, 14, 40, 114, ... 1, 3, 9, 26, 74, ... 2, 6, 17, 48, ... 4, 11, 31, ... 7, 20, ... 13, ... Reorient into the triangle: 1; 1, 2; 2, 3, 5; 4, 6, 9, 14; 7, 11, 17, 26, 40; ... PROG (PARI) lista(nn) = my(va = Vec(-(x-1)^2/(-1+4*x-4*x^2+2*x^3) + O(x^(nn))), v = vector(nn)); v[1] = va; for (n=2, nn, v[n] = vector(nn-n+1, k, v[n-1][k+1] - v[n-1][k]); ); my(list = List()); for (n=1, nn, my(i = n, j = 1); for (k=1, n, listput(list, v[i][j]); i--; j++; ); ); Vec(list); \\ Michel Marcus, Aug 10 2023 CROSSREFS Cf. A000073 (1st column), A117268 (difference rows), A117189 (right diagonal). Sequence in context: A328666 A036716 A026399 * A086363 A174094 A360461 Adjacent sequences: A117264 A117265 A117266 * A117268 A117269 A117270 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Mar 05 2006 EXTENSIONS More terms from Michel Marcus, Aug 10 2023 STATUS approved

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Last modified November 29 06:17 EST 2023. Contains 367422 sequences. (Running on oeis4.)