3693690

Appears in sequences

• a(n) = sigma_2(n)*Fibonacci(n), where sigma_2(n) = A001157(n), the sum of squares of divisors of n.at n=19A203849
• Average of twin prime pairs n having their decimal expansion of the form abcabc or abcabc0 such that n contains three twin primes as divisors.at n=21A235716
• a(n) = period length of the sequence A020639(n^k - 1), k >= 1.at n=87A368811