18399

Appears in sequences

• Generalized Catalan Numbers x^4*A(x)^2 -(1-x+x^4+x^5+x^6+x^7)*A(x) + 1 =0.at n=26A023430
• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 90.at n=34A031588
• a(n) = 46*n^2 - 1.at n=19A158634
• Semiprimes q such that q^2-4 and q^2+4 are also semiprimes.at n=16A173084
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 846", based on the 5-celled von Neumann neighborhood.at n=38A273689