220419

Appears in sequences

• Number of set partitions of [n] such that for each block b the smallest integer interval containing b has at most seven elements and for at least one block c the smallest integer interval containing c has exactly seven elements.at n=5A320557
• a(n) is the number of pairs of twin primes p and p+2 both less than or equal to 10^n such that p is congruent to 1 modulo 4.at n=7A369109