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A227364
a(n) = 1 + 2*3 + 4*5*6 + 7*8*9*10 + ... + ...*n (see Example lines).
7
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
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
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Jul 07 2013
STATUS
approved