91000

Appears in sequences

• Sum of two (possibly negative) cubes in at least 3 ways.at n=14A051383
• Numbers k such that (k, phi(k), sigma(k)) lies on a sphere with integral radius centered at the origin, i.e., k^2 + phi(k)^2 + sigma(k)^2 is a square.at n=8A066785
• Numbers k such that sigma(k)*phi(k)*k is a square.at n=12A114079
• Numbers whose Spanish names include all five vowels exactly once.at n=5A163321
• Expansion of 1 / ((1+x)*(1-x-4*x^2)). (5,4)-Padovan sequence.at n=13A176738
• Numbers n with property that n and 2n are sums of two distinct positive cubes.at n=22A191345
• a(n) = 1*4*7 + 4*7*10 + 7*10*13 + ... (n terms).at n=10A196513
• Composite numbers n with k digits such that each sum of 1 to k digits of n is substring of n.at n=47A205530
• a(0)=a(1)=1, a(n) = least k > a(n-1) such that k*a(n-2) is a triangular number.at n=46A214961
• The Wiener index of the zig-zag polyhex nanotube TUHC_6[2n,2] defined pictorially in Fig. 1 of the Eliasi et al. reference.at n=26A227703
• G.f.: Sum_{n>=0} (x^n - 1)^n * x^n / (1-x)^(n+1).at n=41A243919
• Inflation orbit counts b^{(3)}_n for Danzer's F-type tiling and other 3D cut and project patterns with tau-inflation.at n=7A324488
• Numbers k such that squarefree part of sigma(k) is equal to squarefree part of 2*k.at n=19A331752
• a(n) = n^3 * (n^2 - n + 1).at n=10A382612