OFFSET
1,2
COMMENTS
Partial sums of numbers n such that n^2 is a sum of distinct factorials. The subsequence of primes in this partial sum begins: 59, 659, 1187707. If there is a larger value (the sequence might be finite), a(n)^2 must be greater than 48! (about 1.24139 * 10^61).
FORMULA
EXAMPLE
a(15) = 1 + 3 + 5 + 11 + 12 + 27 + 29 + 71 + 72 + 213 + 215 + 603 + 635 + 1917 + 1183893 is prime.
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Jonathan Vos Post, May 08 2010
STATUS
approved