20307

Appears in sequences

• Numbers k such that x^k + x^2 + 1 is irreducible over GF(2).at n=15A057460
• Triangle of coefficients, read by rows, where the n-th row forms the polynomial P(n,x) = {Sum_{k=1..n} 1/(k+x)}*{Product_{k=1..n} (k+x)}.at n=23A074246
• Triangle read by rows: T(n,m) = number of graphs on n labeled nodes, with m components of size = order. Also number of graphs on n labeled nodes with m unicyclic components.at n=29A106239
• Triangular array T(n,k) giving number of 2-connected graphs with n labeled nodes and k edges (n >= 3, n <= k <= n(n-1)/2).at n=29A123534
• a(n) = A168174(n)-10^12.at n=24A168248
• Number of ways to arrange 4 indistinguishable points on an n X n X n triangular grid so that no four points are in the same row or diagonal.at n=6A194481
• T(n,k) = number of ways to arrange k indistinguishable points on an n X n X n triangular grid so that no four points are in the same row or diagonal.at n=51A194485
• Coefficient table of numerator polynomials of o.g.f.s for partial sums of powers of positive integers.at n=25A196837
• Number of length 4 arrays x(i), i=1..4 with x(i) in i..i+n and no value appearing more than 2 times.at n=10A250353
• Number of factorizations of m^n into exactly four factors, where m is a product of two distinct primes.at n=14A277240
• Prime time numbers on 6-digit clocks: numbers of the form HMMSS where H, MM, SS are primes, H < 24, MM and SS < 60.at n=20A295014
• Number of n X 2 0..1 arrays with every element equal to 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=11A300344
• Triangle read by rows: T(n,k) is the number of simple graphs on n labeled vertices with k edges and without endpoints, n >= 0, 0 <= k <= n*(n-1)/2.at n=58A369928
• Expansion of e.g.f. -log(1-x) * (exp(x) - 1) / (1-x).at n=7A381107