30870

Appears in sequences

• Triangle of coefficients in expansion of (3+7x)^n.at n=18A013624
• a(n) = 49*(n-1)*(n-2)/2.at n=34A027469
• Triangle whose (i,j)-th entry is binomial(i,j)*7^(i-j)*3^j.at n=17A038269
• Triangle read by rows: Stirling2 triangle with scaled diagonals (powers of 7).at n=17A075502
• Third column of triangle A075502.at n=3A075922
• Number of irregular primes (A000928) less than 10^n.at n=5A092901
• Beginning with sequence A096903, choose only those rows such that when a(n) is in factored form all exponents of a(n) are consecutive starting at 1.at n=38A117311
• Triangle read by rows: G(s, rho) = ((s-1)!/s)*Sum_{i=0..s-1} ((s-i)/i!)*(s*rho)^i.at n=25A122525
• Partition number array, called M32(-3), related to A000369(n,m) = |S2(-3;n,m)| (generalized Stirling triangle).at n=35A143173
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 0), (0, -1), (1, -1), (1, 0), (1, 1)}.at n=11A151456
• a(n) is the number of distinct reduced words of length n in the Coxeter group of "Apollonian reflections" in three dimensions.at n=8A154638
• a(n) = binomial(n+1,2)*7^2.at n=35A162942
• Triangle T(n,k) read by rows: T(n,k) is the number of rooted hypertrees on n labeled vertices with k hyperedges, n >= 2, k >= 1.at n=17A210586
• Number of (w,x,y,z) with all terms in {1,...,n} and w>2x and y<=3z.at n=20A212517
• Triangular array read by rows. T(n,k) is the number of functional digraphs on {1,2,...,n} such that no node is at a distance greater than one from a cycle and there are k recurrent elements whose preimage contains only one element, n>=0, 0<=k<=n.at n=30A220222
• Number of (n+2) X 9 0..1 matrices with each 3 X 3 subblock idempotent.at n=15A224558
• Number of tilings of a 4 X n rectangle using L and Z tetrominoes.at n=12A232497
• a(n) = (3*n+7)*n^2.at n=21A257042
• Partition array in Abramowitz-Stegun order for the number of ways of putting n stones into a rectangular m X n grid of squares such that each of the m rows contains at least one stone.at n=34A258152
• Number of (n+2)X(1+2) 0..1 arrays with no 3x3 subblock diagonal sum less than the antidiagonal sum or central row sum less than the central column sum.at n=4A258887