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 A121734 #14 Feb 16 2025 08:33:02
%S A121734 483,209,21,632,650,541,546,281,666,440,397,576,18,251,356,207,532,
%T A121734 361,121,642,288,167,348,505,561,0,108,166,97,492,58,255,632,151,679,
%U A121734 185,141,587,0,549,459,428,549,157,559,121,605,102
%N A121734 Ramanujan tau numbers such that A000594(k) == A000594(k+1) mod 691, or A046694(k) = A046694(k+1).
%C A121734 The corresponding indices k are listed in A121733.
%H A121734 Amiram Eldar, <a href="/A121734/b121734.txt">Table of n, a(n) for n = 1..10000</a>
%H A121734 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TauFunction.html">Ramanujan's Tau Function</a>.
%F A121734 a(n) = mod(A000594(A121733(n)), 691) = A046694(A121733(n)).
%e A121734 a(1) = 483 because the first pair of equal consecutive numbers in A046694 is A046694(184) = A046694(185) = 483.
%t A121734 Do[f=Mod[DivisorSigma[11,n],691];g=Mod[DivisorSigma[11,n+1],691];If[f==g,Print[{n,f}]],{n,1,10000}]
%Y A121734 Cf. A000594, A046694, A121733.
%K A121734 nonn
%O A121734 1,1
%A A121734 _Alexander Adamchuk_, Aug 18 2006