42108

Appears in sequences

• Triangle read by rows giving the sum of the number of k-matchings of the graphs obtained by deleting one edge and its two vertices from the ladder graph L_n = P_2 X P_n in all possible ways.at n=41A318243
• Product_{d|n, A007431(d) > 0} prime(A007431(d)), where A007431 is the Möbius transform of Euler's totient function.at n=55A318838
• a(n) = Sum_{k=0..floor(n/2)} binomial(k+2,2) * binomial(k,2*(n-2*k)).at n=25A392252