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 A143291 Triangle T(n,k), n>=2, 0<=k<=n-2, read by rows: numbers of binary words of length n containing at least one subword 10^{k}1 and no subwords 10^{i}1 with i
 1, 3, 1, 8, 2, 1, 19, 4, 2, 1, 43, 8, 3, 2, 1, 94, 15, 5, 3, 2, 1, 201, 27, 9, 4, 3, 2, 1, 423, 48, 15, 6, 4, 3, 2, 1, 880, 84, 24, 10, 5, 4, 3, 2, 1, 1815, 145, 38, 16, 7, 5, 4, 3, 2, 1, 3719, 248, 60, 24, 11, 6, 5, 4, 3, 2, 1, 7582, 421, 94, 35, 17, 8, 6, 5, 4, 3, 2, 1, 15397, 710, 146, 51, 25, 12, 7, 6, 5, 4, 3, 2, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 COMMENTS T(n,k) = number of subset S of {1,2,...,n+1} such that |S| > 1 and min(S*) = k, where S* is the set {x(2)-x(1), x(3)-x(2), ..., x(h+1)-x(h)} when the elements of S are written as x(1) < x(2) < ... < x(h+1); if max(S*) is used in place of min(S*), the result is the array at A255874. - Clark Kimberling, Mar 08 2015 LINKS Alois P. Heinz, Rows n = 2..142, flattened FORMULA G.f. of column k: x^(k+2) / ((x^(k+1)+x-1)*(x^(k+2)+x-1)). EXAMPLE T (5,1) = 4, because there are 4 words of length 5 containing at least one subword 101 and no subword 11: 00101, 01010, 10100, 10101. Triangle begins:     1;     3,  1;     8,  2,  1;    19,  4,  2, 1;    43,  8,  3, 2, 1;    94, 15,  5, 3, 2, 1;   201, 27,  9, 4, 3, 2, 1;   423, 48, 15, 6, 4, 3, 2, 1; MAPLE as:= proc (n, k) option remember;        if k=0 then 2^n      elif n<=k and n>=0 then n+1      elif n>0 then as(n-1, k) +as(n-k-1, k)      else as(n+1+k, k) -as(n+k, k)        fi      end: T:= (n, k)-> as(n, k) -as(n, k+1): seq(seq(T(n, k), k=0..n-2), n=2..15); MATHEMATICA as[n_, k_] := as[n, k] = Which[ k == 0, 2^n, n <= k && n >= 0, n+1, n > 0, as[n-1, k] + as[n-k-1, k], True, as[n+1+k, k] - as[n+k, k] ]; t [n_, k_] := as[n, k] - as[n, k+1]; Table[Table[t[n, k], {k, 0, n-2}], {n, 2, 14}] // Flatten (* Jean-François Alcover, Dec 11 2013, translated from Maple *) CROSSREFS Columns k=0-10 give: A008466, A143281, A143282, A143283, A143284, A143285, A143286, A143287, A143288, A143289, A143290. Row sums are in A000295. Cf. A141539. Sequence in context: A182510 A112420 A010288 * A258043 A200064 A242072 Adjacent sequences:  A143288 A143289 A143290 * A143292 A143293 A143294 KEYWORD nonn,tabl AUTHOR Alois P. Heinz, Aug 04 2008 STATUS approved

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Last modified August 13 08:18 EDT 2022. Contains 356079 sequences. (Running on oeis4.)