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 A064580 Triangle associated with rooted trees with a degree constraint (A036765). 6
 1, 1, 1, 1, 2, 2, 1, 3, 5, 5, 1, 4, 9, 14, 13, 1, 5, 14, 28, 40, 36, 1, 6, 20, 48, 87, 118, 104, 1, 7, 27, 75, 161, 273, 357, 309, 1, 8, 35, 110, 270, 536, 866, 1100, 939, 1, 9, 44, 154, 423, 951, 1782, 2772, 3441, 2905, 1, 10, 54, 208, 630, 1572, 3310, 5928, 8946, 10900, 9118 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS Row sums = A161898: (1, 2, 5, 14, 41, 124, 384,...). - Gary W. Adamson, Jun 21 2009 Main diagonal is A036765. - Paul D. Hanna, Nov 18 2016 LINKS FORMULA a(n, k) = a(n-1, k)+a(n-1, k-1)+a(n-1, k-2)+a(n-1, k-3) with a(0, 0)=1 and a(n, k)=0 if n

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Last modified May 7 03:48 EDT 2021. Contains 343636 sequences. (Running on oeis4.)