20099

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 23 ones.at n=13A031791
• Number of polyiamonds with n cells that tile the plane by 180-degree rotation (Conway criterion).at n=15A075220
• Number of binary strings of length n with no substrings equal to 0001 0010 or 1101.at n=21A164452
• Numbers of the form p*q, p and q prime with q=2p-3.at n=16A226755
• Number of partitions p of n such that (number of numbers in p of form 3k+1) > (number of numbers in p of form 3k+2).at n=41A241739
• Number of tilings of a 5 X n rectangle using n pentominoes of shapes I, U, X.at n=19A247124
• Intersection of A003052 and A283002.at n=28A283003
• Number of strict trees of weight n with distinct leaves.at n=24A300352
• Numbers of the form ab such that uphi(ab) = a*b where ab is the concatenation of a and b.at n=24A337523
• Odd composite integers m such that U(m)^2 == 1 (mod m) and V(m) == 5 (mod m), where U(m)=A004254(m) and V(m)=A003501(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=5 and b=1, respectively.at n=37A337779
• Odd composite integers m such that A004254(m-J(m,21)) == 0 (mod m) and gcd(m,21)=1, where J(m,21) is the Jacobi symbol.at n=39A340098