27757

Appears in sequences

• Numerator of sum(1/(phi(k)sigma(k)),k=1..n), where phi(k) is the totient function and sigma(k) is the sum of the divisors function.at n=11A104526
• Numbers k such that k^3 contains a pandigital substring.at n=34A115933
• Integers of the form (x^3)/6 + (x^2)/2 + x + 1.at n=18A127876
• Number of (n+1) X 6 binary arrays with consecutive windows of two bits considered as a binary number nondecreasing in every row and column.at n=9A202332
• Breadth-first reading of the subtree rooted at 7 of the tree where each parent node is the arithmetic derivative (A003415) of all its children.at n=47A327977
• a(n) = 1 + Sum_{k=0..n-1} binomial(n+3,k+4) * a(k).at n=7A352862
• G.f. satisfies A(x) = Sum_{n>=1} A(x^3)^n / A(x^(2*n)), with A(0) = 0 and A'(0) = 1.at n=29A383376