18200

Appears in sequences

• a(n) = floor( n*(n-1)*(n-2)*(n-3)/27 ).at n=28A011937
• a(n) = 7*a(n-1) + a(n-2), with a(0)=1 and a(1)=7.at n=5A054413
• Numbers k that, when expressed in base 5 and then interpreted in base 7, give a multiple of k.at n=10A062929
• Number of hexagonal regions in regular n-gon with all diagonals drawn.at n=50A067153
• Related to series for Laplace limit constant.at n=5A074768
• Number of ways to partition 2n+1 into distinct positive integers.at n=32A078408
• Number of ways to partition 4*n+1 into distinct positive integers.at n=16A078409
• a(n) = Fibonacci(6, n).at n=7A124152
• a(n) = Product_{k>=0} (1 + floor(n/2^k)).at n=24A132269
• Numbers k such that k^2 + 1 is a Sarrus number (pseudoprime to base 2).at n=6A135590
• Number of rooted trees with n points and exactly k specified colors: C(n,k), 1<=n, 1<=k<=n.at n=18A141610
• 10 times pentagonal numbers: a(n) = 5*n*(3*n-1).at n=35A153780
• Modified Fibonomial matrix.at n=40A154218
• Number of permutations of 1..n containing the relative rank sequence { 146352 } at any spacing.at n=3A159120
• Number of permutations of 1..n containing the relative rank sequence { 153642 } at any spacing.at n=3A159126
• Array A(n,k) = n*A(n,k-1) + A(n,k-2) read by upward antidiagonals, starting A(n,0) = 0, A(n,1) = 1.at n=84A172236
• Triangle t(n,k) read by rows: fibonomial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Fibonacci sequence with multiplier m=7.at n=22A172345
• Triangle t(n,k) read by rows: fibonomial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Fibonacci sequence with multiplier m=7.at n=26A172345
• Numbers whose sum of triangular divisors is also a divisor and greater than 1.at n=23A209311
• Antidiagonal sums of the convolution array A213778.at n=23A213780