30395

Appears in sequences

• Triangle read by rows: semigroups of order n with k idempotents, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).at n=26A058123
• Number of permutations of length n which avoid the patterns 2134, 3421, 4312.at n=16A116766
• Partial sums of A005109.at n=25A172167
• Numbers k such that both Sum_{i=1..k} i*prime(i) and Sum_{i=1..k} (k+1-i)*prime(i) are prime.at n=40A356178