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 A181512 Irregular triangle a(n,k) = A181415(n,k) / A036040(n,k). 2
 1, 1, 1, 1, 2, 2, 1, 3, 3, 6, 6, 1, 4, 4, 12, 12, 24, 24, 1, 5, 5, 5, 20, 20, 20, 60, 60, 120, 120, 1, 6, 6, 6, 30, 30, 30, 30, 120, 120, 120, 360, 360, 720, 720, 1, 7, 7, 7, 7, 42, 42, 42, 42, 42, 210, 210 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS This is an irregular table related to labeled rooted trees and to Bell numbers. A181511 contains the same values, without repetition. LINKS FORMULA sum_{k=1.. A000041(n)} a(n,k) = A181513(n). (Row sums) EXAMPLE 1; 1,1; 1,2,2; 1,3,3,6,6; 1,4,4,12,12,24,24; 1,5,5,5,20,20,20,60,60,120,120; 1,6,6,6,30,30,30,30,120,120,120,360,360,720,720; CROSSREFS Cf. A181511, A181513 (row sums). Sequence in context: A109380 A167754 A011020 * A076019 A071453 A212306 Adjacent sequences:  A181509 A181510 A181511 * A181513 A181514 A181515 KEYWORD nonn,tabf AUTHOR Alford Arnold, Oct 26 2010 STATUS approved

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Last modified October 21 17:52 EDT 2020. Contains 337919 sequences. (Running on oeis4.)