This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A055682 #18 Apr 25 2024 05:18:55 %S A055682 0,-1,1,1,5,2,10,7,14,13,24,13,32,28,34,33,52,37,62,47,64,67,86,57,94, %T A055682 90,100,92,126,92,140,118,141,144,159,125,187,174,187,162,220,176,237, %U A055682 207,223,239,274,208,286,260,292,276,331,276,335,299 %N A055682 a(n) = floor(n*sqrt(n)) - sigma(n), where sigma(n) is the sum of the divisors of n (A000203). %C A055682 Always > 0 for n > 2. %D A055682 József Sándor, Dragoslav S. Mitrinovic, and Borislav Crstici, Handbook of Number Theory I, Springer Science & Business Media, 2005, Chapter III, p. 77, section III.1.1.b. %H A055682 C. C. Lindner, <a href="https://www.jstor.org/stable/2315486">Problem E1888</a>, Amer. Math. Monthly, 73 (1966), 538; <a href="https://www.jstor.org/stable/2313649">solution</a> by A. Bager and S. Russ, op. cit. 74 (1967), 1143. %H A055682 N. J. A. Sloane, <a href="https://arxiv.org/abs/2301.03149">"A Handbook of Integer Sequences" Fifty Years Later</a>, arXiv:2301.03149 [math.NT], 2023, p. 6. %t A055682 a[n_] := Floor[n*Sqrt[n]] - DivisorSigma[1, n]; Array[a, 100] (* _Amiram Eldar_, Apr 25 2024 *) %o A055682 (PARI) a(n)=sqrtint(n^3)-sigma(n) \\ _Charles R Greathouse IV_, Feb 14 2013 %Y A055682 Cf. A000203, A057641, A058208. %K A055682 sign %O A055682 1,5 %A A055682 _N. J. A. Sloane_, Nov 29 2000