1230957

Appears in sequences

• a(n) = (-1)^(n+1)/5 * Sum_{k=1..2n} binomial(2n+1,k)*B(k)*5^k where B(k) are the Bernoulli numbers.at n=4A069990
• a(1)=1, a(n) = a(n-1) + n^4 if n odd, a(n) = a(n-1) + n^3 if n is even.at n=24A140160