507360

Appears in sequences

• Triangle read by rows: T(n, k) = number of matchings of 2n people with partners (of either sex) such that exactly k couples are left together.at n=48A055140
• Numbers k such that k-1, k+1, 2*k-1, 2*k+1, 4*k-1 and 4*k+1 are all prime.at n=4A069175
• Column 5 of array in A133713.at n=6A133720
• Column 6 of triangle in A133721.at n=42A133733
• Expansion of e.g.f. exp( x^2/(1-x)^3 ) / (1-x).at n=7A375172