20368

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 19 ones.at n=16A031787
• Numbers n such that n | (sigma_5(n) - phi(n)^5).at n=23A055699
• Numbers k such that k | sigma_11(k) - phi(k)^11.at n=15A055705
• Group the composite numbers so that the sum of the n-th group is a multiple of the n-th prime: (4), (6), (8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22), (24, 25), (26, 27, 28, 30, 32), (33, 34, ...), ... Sequence gives the group sum divided by n-th prime for the n-th group.at n=45A074127
• G.f.: A(x) = ( G(x)^7 - G(x^7) - 7*x*((1-x^6)/(1-x))/(1-x^7) )/(49*x^2) where G(x) is the g.f. of A110635.at n=10A111584
• a(n) = 1 + n + binomial(n+3,5).at n=18A154322
• Numbers which are representable as a sum of nineteen but no fewer consecutive nonnegative integers.at n=22A270303
• Number of n X 4 0..2 arrays with no element equal to any value at offset (-1,0) (0,-1) or (-2,-2) and new values introduced in order 0..2.at n=8A274854
• Number of integer partitions of n that are empty, have smallest part not dividing all the others, or greatest part not divisible by all the others.at n=37A343346
• G.f. satisfies A(x) = 1 + x^3 + x*A(x)^2.at n=10A367042