55646

Appears in sequences

• Numbers k such that the value pi(k), the number of primes <= k, can be obtained deleting some of the repeating adjacent digits of k.at n=5A113898
• Numbers k whose decimal representation ends with that of pi(k) (where pi denotes the prime counting function A000720).at n=16A306572
• a(n) = Sum_{k=1..n} 2^k * sigma(k), where sigma(k) = A000203(k).at n=10A324915
• G.f. satisfies A(x) = 1 + x^3 + x*A(x)^4.at n=7A367043