23940

Appears in sequences

• a(n) = n*(n+1)*(n+2)*(n+3)/6.at n=18A033488
• Number of nonnegative solutions of x1^2 + x2^2 + ... + x9^2 = n.at n=31A045851
• Reduced denominators of the coefficients in a series expansion for Gamma[x].at n=16A054380
• Number of n-bead necklaces with exactly six different colored beads.at n=7A056286
• Number of primitive (period n) n-bead necklaces with exactly six different colored beads.at n=7A056291
• Numbers n such that phi(4n+1) = sigma(n).at n=7A067234
• Numbers k such that phi(k) = tau(k)^2.at n=29A068560
• a(n) = n*(n - 1)*(n + 2)/2.at n=35A077414
• Numbers k such that 2k-1 divides 2^k-1.at n=18A081856
• Triangle read by rows: T(n,k) is the number of n-bead necklaces with exactly k different colored beads.at n=33A087854
• Number of noncrossing connected graphs on n nodes having exactly two interior faces.at n=4A089433
• Triangle read by rows: T(n,k) (n >= 2, k >= 0) is the number of non-crossing connected graphs on n nodes on a circle, having k interior faces. Rows are indexed 2,3,4,...; columns are indexed 0,1,2,....at n=23A089434
• a(n) = 997*n + 1009.at n=23A100776
• Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(1,1), d=(1,-2) and have k peaks (i.e., ud's).at n=48A108767
• Area common to integer-sided isosceles triangles (x,x,y) and (x,x,z=y+2d), sorted on x > z/2, d being positive.at n=34A120644
• Triangle T(n, k) = (binomial(n,2))! / (k! * abs(k+1 - binomial(n,2))!), read by rows.at n=24A123146
• Coefficients of the series giving the best rational approximations to sqrt(11).at n=1A123482
• Amicable triples: numbers such that sigma(x) = sigma(y) = sigma(z) = x+y+z, x<y<z. We order these triples according to the common value of sigma. Sequence gives x numbers.at n=3A125490
• Triangle read by rows: T(n,k) (n >= 2, 1 <= k <= 2n-3) is the number of non-crossing connected graphs on n nodes on a circle, having k edges. Rows are indexed 2,3,4,...; columns are indexed 0,1,2,....at n=44A127537
• A129065 with v=n instead of v=1: recursive polynomial coefficient triangle.at n=49A136453