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 A152547 Triangle, read by rows, derived from Pascal's triangle (see g.f. and example for generating methods). 2
 1, 2, 3, 1, 4, 2, 2, 5, 3, 3, 3, 1, 1, 6, 4, 4, 4, 4, 2, 2, 2, 2, 2, 7, 5, 5, 5, 5, 5, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 1, 8, 6, 6, 6, 6, 6, 6, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 9, 7, 7, 7, 7, 7, 7, 7, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Paul D. Hanna, Table of rows 0..14 listed as n, a(n) for n = 0..7059 FORMULA G.f. of row n: Sum_{k=0..n} (x^binomial(n,k) - 1)/(x-1) = Sum_{k=0..binomial(n,n\2)-1} T(n,k)*x^k. A152548(n) = Sum_{k=0..C(n,[n/2])-1} T(n,k)^2 = Sum_{k=0..[(n+1)/2]} C(n+1, k)*(n+1-2k)^3/(n+1). EXAMPLE The number of terms in row n is C(n,[n/2]). Triangle begins: [1], [2], [3,1], [4,2,2], [5,3,3,3,1,1], [6,4,4,4,4,2,2,2,2,2], [7,5,5,5,5,5,3,3,3,3,3,3,3,3,3,1,1,1,1,1], [8,6,6,6,6,6,6,4,4,4,4,4,4,4,4,4,4,4,4,4,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2], [9,7,7,7,7,7,7,7,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1], ... ILLUSTRATION OF GENERATING METHOD. Row n is derived from the binomial coefficients in the following way. Place markers in an array so that the number of contiguous markers in row k is C(n,k) and then count the markers along columns. For example, row 6 of this triangle is generated from C(6,k) like so: ------------------------------------------ 1: o - - - - - - - - - - - - - - - - - - - 6: o o o o o o - - - - - - - - - - - - - - 15:o o o o o o o o o o o o o o o - - - - - 20:o o o o o o o o o o o o o o o o o o o o 15:o o o o o o o o o o o o o o o - - - - - 6: o o o o o o - - - - - - - - - - - - - - 1: o - - - - - - - - - - - - - - - - - - - ------------------------------------------ Counting the markers along the columns gives row 6 of this triangle: [7,5,5,5,5,5,3,3,3,3,3,3,3,3,3,1,1,1,1,1]. Continuing in this way generates all the rows of this triangle. ... Number of repeated terms in each row of this triangle forms A008315: 1; 1; 1, 1; 1, 2; 1, 3, 2; 1, 4, 5; 1, 5, 9, 5; 1, 6, 14, 14; 1, 7, 20, 28, 14;... PROG (PARI) {T(n, k)=polcoeff(sum(j=0, n, (x^binomial(n, j) - 1)/(x-1)), k)} for(n=0, 10, for(k=0, binomial(n, n\2)-1, print1(T(n, k), ", ")); print("")) CROSSREFS Cf. A152548 (row squared sums), A008315; A152545. Sequence in context: A273620 A104705 A143361 * A083906 A160541 A286001 Adjacent sequences:  A152544 A152545 A152546 * A152548 A152549 A152550 KEYWORD nonn,tabf AUTHOR Paul D. Hanna, Dec 14 2008 STATUS approved

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Last modified April 25 21:06 EDT 2019. Contains 322461 sequences. (Running on oeis4.)