cp's OEIS Frontend

A241928 a(n) = smallest k such that lambda(n+k) = lambda(k).

%I A241928 #5 May 09 2014 22:51:23
%S A241928 1,4,3,4,3,6,7,4,3,5,5,9,13,7,5,8,17,6,9,4,3,11,23,16,5,13,9,14,7,10,
%T A241928 31,13,9,17,5,36,37,10,13,20,41,14,5,16,15,23,9,36,7,10,17,13,52,9,5,
%U A241928 7,13,14,45,20,61,31,9,16,7,18,45,17,23,10,71,45,39
%N A241928 a(n) = smallest k such that lambda(n+k) = lambda(k).
%C A241928 Lambda(n) is the Carmichael lambda function(A002322).
%C A241928 It is highly probable that a solution exists for each n>0.
%C A241928 The corresponding values of lambda(k) are 1, 2, 2, 2, 2, 2, 6, 2, 2, 4, 4, 6, 12, 6, 4, 2, 16, 2, 6, 2, 2, 10, 22, 4, 4, 12, 6, 6, 6, 4, 30, ...
%H A241928 Michel Lagneau, <a href="/A241928/b241928.txt">Table of n, a(n) for n = 1..10000</a>
%e A241928 a(29) = 7 because lambda(29+7) = lambda(7) = 6.
%p A241928 with(numtheory):for n from 1 to 70 do:ii:=0:for k from 1 to 10^8 while(ii=0) do:if lambda(k) = lambda(k+n) then ii:=1:printf(`%d, `,k):else fi:od:od:
%t A241928 klambda[n_]:=Module[{k=1}, While[CarmichaelLambda[n+k]!= CarmichaelLambda [k], k++]; k]; Array[klambda, 70]
%Y A241928 Cf. A002322, A007015, A173695.
%K A241928 nonn
%O A241928 1,2
%A A241928 _Michel Lagneau_, May 02 2014