139528

Appears in sequences

• a(n) = Sum_{i=1..n, j=1..n, gcd(i,j)=1} (n+1-i)*(n+1-j).at n=29A115004
• Number of integers k such that floor((r^n)/k)=n, where r = golden ratio = (1+sqrt(5))/2.at n=39A182613
• Expansion of e.g.f. exp(x*cosh(x) + x^2*sinh(x)/2).at n=9A389688