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 A227367 a(0)=1, a(n+1) = a(0) + a(1)*a(2) + a(3)*a(4)*a(5) + a(6)*a(7)*a(8)*a(9) + ... + ...*a(n). 5
 1, 1, 2, 3, 6, 21, 381, 762, 290703, 84397476747, 7122934049104967061783, 14245868098209934123566, 101472378935797762635619628499635817245339961, 10296643686890133479148472187437767614663729545766251948487237380959682684821520304732841 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..13. EXAMPLE a(1) = a(0) = 1 a(2) = a(0) + a(1) = 2 a(3) = a(0) + a(1)*a(2) = 3 a(4) = a(0) + a(1)*a(2) + a(3) = 1 + 2 + 3 = 6 a(5) = a(0) + a(1)*a(2) + a(3)*a(4) = 1 + 2 + 18 = 21 a(6) = a(0) + a(1)*a(2) + a(3)*a(4)*a(5) = 1 + 2 + 18*21 = 381 PROG (Python) a = [1]*99 for n in range(20): sum = i = 0 k = 1 while i<=n: product = 1 for x in range(k): product *= a[i] i += 1 if i>n: break sum += product k += 1 a[n+1] = sum print(str(a[n]), end=', ') CROSSREFS Cf. A227363, A227364, A227365, A227366. Sequence in context: A013155 A303224 A007501 * A270397 A278106 A015773 Adjacent sequences: A227364 A227365 A227366 * A227368 A227369 A227370 KEYWORD nonn AUTHOR Alex Ratushnyak, Jul 08 2013 STATUS approved

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Last modified September 21 21:03 EDT 2023. Contains 365503 sequences. (Running on oeis4.)