-1048571

Appears in sequences

• a(n)=-a(n-1)+4*a(n-2)+4*a(n-3).at n=20A136249
• Numerators of 1/2 + sum(chi(p)^(4*n / (p-1))/p) where the sum is over primes p of the form 4k+1 such that p-1 divides 4*n and the numbers chi(p) are given by A002172.at n=18A274398