OFFSET
1,3
COMMENTS
a(n) is always an integer.
Are there any primes p such that p^3 divides A006134(p-1) - Legendre(p, 3)?
EXAMPLE
a(1) = (binomial(0, 0) + binomial(2, 1) + 1)/4 = 4/4 = 1.
a(2) = (binomial(0, 0) + binomial(2, 1) + binomial(4, 2))/9 = 9/9 = 1.
a(3) = (binomial(0, 0) + binomial(2, 1) + binomial(4, 2) + binomial(6, 3) + binomial(8, 4) + 1)/25 = 100/25 = 4.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Jianing Song, Oct 18 2018
STATUS
approved