20783

Appears in sequences

• Numbers k such that 179*2^k+1 is prime.at n=27A032466
• Denominators of continued fraction convergents to sqrt(382).at n=11A041725
• Frobenius number of the numerical semigroup generated by three consecutive pentagonal numbers.at n=16A069757
• Positive fundamental solution y(n) of the generalized Pell equation X^2 - D(n) Y(n) = 2 with D(n) = A261246(n).at n=38A261248
• The y member of the positive proper fundamental solution (x = x2(n), y = y2(n)) of the second class for the Pell equation x^2 - D(n)*y^2 = +8 for even D(n) = A264354(n).at n=38A264439
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 555", based on the 5-celled von Neumann neighborhood.at n=26A272922
• y-value of the smallest solution to 2*x^2 - p*y^2 = (-1)^((p+1)/4), p = A002145(n).at n=22A306619