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A227366 a(0)=1, a(n+1) = a(n) + a(n-1)*a(n-2) + a(n-3)*a(n-4)*a(n-5) + a(n-6)*a(n-7)*a(n-8)*a(n-9) + ... + ...*a(0). 4
1, 1, 2, 3, 6, 13, 33, 118, 584, 4714, 76206, 2879841, 364389490, 220150411628, 1049813737275512, 80222580570107370160, 231117086585854944888597249, 84218767584329653007205530276477742, 18540809099930664963747242025045529905738135516 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..18.

EXAMPLE

a(1) = a(0) = 1

a(2) = a(1) + a(0) = 2

a(3) = a(2) + a(1)*a(0) = 3

a(4) = a(3) + a(2)*a(1) + a(0) = 3 + 2 + 1 = 6

a(5) = a(4) + a(3)*a(2) + a(1)*a(0) = 6 + 3*2 + 1 = 13

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[n-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, A227367.

Sequence in context: A296531 A220699 A202086 * A171878 A117403 A002877

Adjacent sequences:  A227363 A227364 A227365 * A227367 A227368 A227369

KEYWORD

nonn,changed

AUTHOR

Alex Ratushnyak, Jul 08 2013

STATUS

approved

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Last modified May 12 04:27 EDT 2021. Contains 343810 sequences. (Running on oeis4.)