19865

Appears in sequences

• Number of subsets of { 1, ..., n } containing an arithmetic progression of length 4.at n=15A018789
• Quasi-Carmichael numbers to base -7: squarefree composites n such that prime p|n ==> p+7|n+7.at n=9A029567
• Number of 6 X 6 binary matrices with n=0...36 ones up to row and column permutations.at n=15A052370
• Number of 6 X 6 binary matrices with n=0...36 ones up to row and column permutations.at n=21A052370
• Numbers n such that n | 10^n + 9^n + 8^n + 7^n + 6^n.at n=41A057252
• Number of 4 X 4 matrices with nonnegative integer entries and all row sums equal to n, up to row and column permutation.at n=5A058390
• a(n) is the smallest k such that number of non-unitary prime divisors of central binomial coefficient, A000984(k) = C(2*k,k) equals n.at n=31A081393
• a(n) = (n^3 + 24*n^2 + 65*n + 36)/6.at n=42A087863
• Largest number that is not the sum of five n-gonal numbers.at n=28A118367
• Number of 2-sided strip polytans with n cells.at n=11A151521
• Positive numbers y such that y^2 is of the form x^2+(x+833)^2 with integer x.at n=36A156835
• Least number of steps required in 2D prime walk for it to cross itself n times.at n=7A268463
• Array read by rows: T(n,k) is the number of nonisomorphic n X n matrices with nonnegative integer entries and row sums k under row and column permutations, (n >= 1, k >= 0).at n=39A318951
• Non-isomorphic proper colorings of the 3 X 3 grid graph using at most n colors under rotational and reflectional symmetries.at n=4A321244
• Odd numbers of the form k * reverse(k) (where reverse(k) is the binary reversal of k, A030101(k)).at n=44A331587
• a(1) = 1, then multiply, subtract, and add 2, 3, 4; 5, 6, 7; ... in that order.at n=14A362272
• Numbers m such that Stern polynomial B(m,x) has no irreducible polynomial factors that themselves are Stern polynomials. The initial a(1) = 1 is included by convention.at n=25A389918