19357

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 49.at n=24A020388
• Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 13.at n=26A051978
• a(n) = (2*n^3 + 5*n^2 + 7*n)/2.at n=25A162264
• G.f. satisfies: A(x) = B(x*A(x)), where B(x) is the g.f. of A184506.at n=9A184508
• G.f.: exp( Sum_{n>=1} Sum_{k>=1} sigma(n)^k * x^(n*k) / n ).at n=15A185301
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 107", based on the 5-celled von Neumann neighborhood.at n=30A270166
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 878", based on the 5-celled von Neumann neighborhood.at n=36A273741
• Odd semiprimes k = p*q such that k = A325820(p,q), with p, q primes > 3, and A325820 is the carryless base-3 multiplication.at n=47A391331