A227365 a(n) = 0 + 1*2 + 3*4*5 + 6*7*8*9 + ... + ...*n.

0, 1, 2, 5, 14, 62, 68, 104, 398, 3086, 3096, 3196, 4406, 20246, 243326, 243341, 243566, 247406, 316766, 1638686, 28150526, 28150547, 28150988, 28161152, 28405550, 34526126, 193916126, 4503821726, 4503821754, 4503822538, 4503846086, 4504576886, 4527986846, 5301270686

Offset: 0

Author

Alex Ratushnyak, Jul 07 2013

Keywords

• nonn

Examples

			a(4) = 0 + 1*2 + 3*4 = 14.
a(5) = 0 + 1*2 + 3*4*5 = 62.
a(6) = 0 + 1*2 + 3*4*5 + 6 = 68.
		

Links

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

Crossrefs

Cf. A227363, A227364, A227366, A227367.

Programs

Python

for n in range(55):
  sum = i = 0
  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=',')