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 A275330 Triangle read by rows, T(n,k) = t(n-k+1)*Sum_{d|k} d*t(d) with t = A000081, for n>=1 and 1<=k<=n. 1
 1, 1, 3, 2, 3, 7, 4, 6, 7, 19, 9, 12, 14, 19, 46, 20, 27, 28, 38, 46, 129, 48, 60, 63, 76, 92, 129, 337, 115, 144, 140, 171, 184, 258, 337, 939, 286, 345, 336, 380, 414, 516, 674, 939, 2581, 719, 858, 805, 912, 920, 1161, 1348, 1878, 2581, 7238 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS EXAMPLE Table starts: [n] [k=1,2,...] row sum [1] [1] 1 [2] [1, 3] 4 [3] [2, 3, 7] 12 [4] [4, 6, 7, 19] 36 [5] [9, 12, 14, 19, 46] 100 [6] [20, 27, 28, 38, 46, 129] 288 [7] [48, 60, 63, 76, 92, 129, 337] 805 [8] [115, 144, 140, 171, 184, 258, 337, 939] 2288 [9] [286, 345, 336, 380, 414, 516, 674, 939, 2581] 6471 PROG (Sage) @cached_function def t():     n = 1     b = [0, 1]     while True:         S = [b[n-k+1]*sum(d*b[d] for d in divisors(k)) for k in (1..n)]         b.append(sum(S)//n)         yield S         n += 1 t_list = t() for n in (1..12): print(next(t_list)) CROSSREFS T(n,0) = A000081(n). T(n,n) = A209397(n). Sum_k T(n,k) = A095350(n+1). Cf. A275331. Sequence in context: A084388 A136389 A332057 * A141863 A071010 A215934 Adjacent sequences:  A275327 A275328 A275329 * A275331 A275332 A275333 KEYWORD nonn,tabl AUTHOR Peter Luschny, Aug 18 2016 STATUS approved

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Last modified June 5 06:41 EDT 2020. Contains 334828 sequences. (Running on oeis4.)