A227364 a(n) = 1 + 2*3 + 4*5*6 + 7*8*9*10 + ... + ...*n (see Example lines).

0, 1, 3, 7, 11, 27, 127, 134, 183, 631, 5167, 5178, 5299, 6883, 29191, 365527, 365543, 365799, 370423, 458551, 2226007, 39435607, 39435629, 39436113, 39447751, 39739207, 47329207, 252562807, 6006997207, 6006997236, 6006998077, 6007024177, 6007860247, 6035477527, 6975328087

Offset

0,3

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Example

a(5) = 1 + 2*3 + 4*5 = 27;
a(6) = 1 + 2*3 + 4*5*6 = 127;
a(7) = 1 + 2*3 + 4*5*6 + 7 = 134.

Prog

(Python)
for n in range(55):
  sum = 0
  i = k = 1
  while i<=n:
    product = 1
    for x in range(k):
      product *= i
      i += 1
      if i>n: break
    sum += product
    k += 1
  print(str(sum), end=', ')

Crossrefs

Cf. A227363, A227365, A227366, A227367, A228958.

Sequence in context: A001645 A103798 A093361 * A051202 A211674 A035095

Adjacent sequences: A227361 A227362 A227363 * A227365 A227366 A227367

Keyword

nonn

Author

Alex Ratushnyak, Jul 07 2013

Status

approved