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 A261840 Number of compositions of n into distinct parts where each part i is marked with a word of length i over a binary alphabet whose letters appear in alphabetical order. 2
 1, 2, 3, 16, 21, 50, 205, 292, 587, 1110, 4535, 5980, 12447, 20910, 40195, 142520, 196291, 372042, 635081, 1128872, 1873245, 6537466, 8553639, 16333532, 26470861, 46629886, 73222631, 127947300, 385293581, 518212198, 939401193, 1516760160, 2564361235 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Also matrices with two rows of nonnegative integers with distinct positive column sums and total element sum n. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..5000 MAPLE b:= proc(n, i, p) option remember; `if`(i*(i+1)/2n, 0, b(n-i, i-1, p+1)*(i+1)))) end: a:= n-> b(n\$2, 0): seq(a(n), n=0..40); CROSSREFS Column k=2 of A261835. Sequence in context: A171458 A044905 A045877 * A100643 A067037 A117926 Adjacent sequences: A261837 A261838 A261839 * A261841 A261842 A261843 KEYWORD nonn AUTHOR Alois P. Heinz, Sep 03 2015 STATUS approved

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Last modified April 20 03:59 EDT 2024. Contains 371798 sequences. (Running on oeis4.)