263140

Appears in sequences

• G.f. satisfies: A(x) = Sum_{n>=0} x^n * A(x)^(n*(n+1)/2).at n=10A107591
• First class of all proper positive solutions y1(n) = a(n) of the Pell equation x^2 - 7*y^2 = 9.at n=4A307169