561513

Appears in sequences

• Positive integers k such that (k+1)^4 has a divisor congruent to -1 modulo k.at n=60A350916
• a(0) = 1, a(1) = 9, and a(n) = 16*a(n-1) - a(n-2) - 4 for n >= 2.at n=5A350925