1250656

Appears in sequences

• Expansion of (1+x^4*C^4)*C^4, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.at n=11A071757
• Octagonal numbers of the form C*(3C - 2) with 3C - 2 = k^2 and C a composite number.at n=20A125511
• Cyclops octagonal numbers: a(n) = n*(3*n-2) with one "zero" digit in the middle.at n=12A285767