1352540

Appears in sequences

• Number of 2n-bead black-white reversible strings with n black beads.at n=12A032123
• Central column of Losanitsch's triangle A034851.at n=24A034872
• a(n) = Sum_{k=0..n} binomial(2*n,2*k)^2.at n=6A098772
• Number of n-element subsets of [2n] having an even sum.at n=12A119358
• Number of bracelets (turn over necklaces) with n beads: 1 blue, 12 green, and r = n - 13 red.at n=12A141783