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%I #13 Jan 26 2020 11:04:14
%S 483,209,21,632,650,541,546,281,666,440,397,576,18,251,356,207,532,
%T 361,121,642,288,167,348,505,561,0,108,166,97,492,58,255,632,151,679,
%U 185,141,587,0,549,459,428,549,157,559,121,605,102
%N Ramanujan tau numbers such that A000594(k) == A000594(k+1) mod 691, or A046694(k) = A046694(k+1).
%C The corresponding indices k are listed in A121733.
%H Amiram Eldar, <a href="/A121734/b121734.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TauFunction.html">Ramanujan's Tau Function</a>.
%F a(n) = mod(A000594(A121733(n)), 691) = A046694(A121733(n)).
%e a(1) = 483 because the first pair of equal consecutive numbers in A046694 is A046694(184) = A046694(185) = 483.
%t Do[f=Mod[DivisorSigma[11,n],691];g=Mod[DivisorSigma[11,n+1],691];If[f==g,Print[{n,f}]],{n,1,10000}]
%Y Cf. A000594, A046694, A121733.
%K nonn
%O 1,1
%A _Alexander Adamchuk_, Aug 18 2006