A239580 - OEIS

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A239580

Numbers k such that A227364(k) = 1 + 2*3 + 4*5*6 + 7*8*9*10 + ... + ...*k is a prime.

0

2, 3, 4, 6, 9, 10, 13, 14, 15, 18, 30, 32, 54, 58, 59, 81, 85, 128, 140, 203, 204, 206, 209, 223, 286, 305, 343, 350, 367, 397, 399, 451, 453, 506, 534, 656, 676, 698, 730, 756, 845, 849, 878, 944, 1020, 1040, 1091, 1248, 1256, 1300, 1310, 1326, 1364, 1406, 1535

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..55.

PROG

(Python)

import sympy

from sympy import isprime

for n in range(10000):

sum = 0

i = k = 1

while i<=n:

product = n

for x in range(k):

product *= i

i += 1

if i>n: break

sum += product

k += 1

if isprime(sum): print str(n)+', ',

CROSSREFS

Sequence in context: A128399 A051404 A046097 * A337724 A175515 A241241

Adjacent sequences: A239577 A239578 A239579 * A239581 A239582 A239583

KEYWORD

nonn

AUTHOR

Alex Ratushnyak, Mar 21 2014

STATUS

approved