20941

Appears in sequences

• Composite and every divisor (except 1) contains the digit 4.at n=13A062670
• a(n) = (3+n)*(2 + 33*n + n^2)/6.at n=40A101860
• Numbers k such that R_(k+2) + 2*10^k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=10A256926
• MM-numbers of crossing set partitions.at n=22A324324
• Number of integer partitions of n such that the dual of the multiset partition obtained by factoring each part into prime numbers is a weak antichain.at n=39A326978
• G.f. satisfies: A(x) = 1/(1 - x/(1 - x*A(x))^4)^2.at n=6A349023