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

Author

Alex Ratushnyak, Jul 07 2013

Keywords

• nonn

Examples

			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.
		

Links

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

Crossrefs

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

Programs

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=',')