74880

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Fibonacci numbers), t = A014306.at n=45A024467
• s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = A014306.at n=44A025087
• Floor( exp(13/21)*n! ).at n=7A030844
• Number of aperiodic necklaces with n labeled beads of 5 colors.at n=4A032324
• E.g.f. satisfies A(x) = x*(1+A(A(x))), A(0)=0.at n=5A035049
• Number of squares (of another matrix) in the group GL(2,Z_n) described in sequence A000252.at n=31A068516
• Numbers k such that phi(k) = 2*tau(k)^2.at n=33A068564
• Numbers k that divide tau(k)*sigma(k).at n=44A071707
• The following triangle contains n smallest numbers with the prime signature of n!. Sequence contains the triangle by rows.at n=31A111467
• Expansion of g.f.: (1 + x + x^2)/(1 - 2*x - 2*x^2).at n=11A121907
• a(1)=1, a(n)=a(n-1)+n^1 if n odd, a(n)=a(n-1)+ n^4 if n is even.at n=14A140146
• Number of permutations of {1,2,...,n} having no consecutive triples of the form (odd, even, odd) or (even, odd, even).at n=9A152876
• Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k consecutive triples of the form (odd,even,odd) and (even,odd,even) (0<=k<=n-2).at n=30A152877
• Triangle T(n, k) = 2*n*binomial(2*n-k, k)*(n-k)!/(2*n-k), with T(0, 0) = 2, read by rows.at n=38A156995
• E.g.f.: exp(6*arcsin(x)).at n=6A166748
• E.g.f.: exp(6*arcsin(x))-6*arcsin(x).at n=6A176696
• T(n,k) = number of (n+1) X (k+1) 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases.at n=36A205823
• Record values of gcd(sigma(n), phi(n)) (A009223).at n=33A222712
• Integer areas of integer-sided triangles where two sides are of square length.at n=27A232461
• a(n) = n! * [x^n] exp(n*arcsin(x)).at n=6A293191