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 A126845 #9 Jan 05 2025 01:10:58 %S A126845 1,22,22,0,0,1,0,1,0,0,0,0,22,0,0,22,0,0,0,0,0,0,1,22,1,1,1,0,22,0,22, %T A126845 0,0,0,0,0,0,0,1,0,22,0,0,0,0,22,22,1,1,22,0,0,0,22,0,0,0,1,2,0,0,1,0, %U A126845 1,0,0,0,0,22,0,22,0,22,0,22,0,0,22,0,0,22,1,0,0,0,0,1,0,0,0,0,0,1,1,0,0,0 %N A126845 Ramanujan numbers (A000594) read mod 23. %D A126845 G. H. Hardy, Ramanujan, Twelve Lectures on Subjects Suggested by His Life and Work, Cambridge, 1940, p. 166. %H A126845 Amiram Eldar, <a href="/A126845/b126845.txt">Table of n, a(n) for n = 1..10000</a> %H A126845 H. P. F. Swinnerton-Dyer, <a href="http://dx.doi.org/10.1007/978-3-540-37802-0_1">On l-adic representations and congruences for coefficients of modular forms</a>, pp. 1-55 of Modular Functions of One Variable III (Antwerp 1972), Lect. Notes Math., 350, 1973. %F A126845 a(n) = 0 if Legendre symbol (n,23) = A011586(n) = -1 (Hardy, 1940). - _Amiram Eldar_, Jan 04 2025 %t A126845 a[n_] := Mod[RamanujanTau[n], 23]; Array[a, 100] (* _Amiram Eldar_, Jan 04 2025 *) %o A126845 (PARI) a(n) = ramanujantau(n) % 23; \\ _Amiram Eldar_, Jan 04 2025 %Y A126845 Cf. A000594, A011586. %K A126845 nonn %O A126845 1,2 %A A126845 _N. J. A. Sloane_, Feb 25 2007