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

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, 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, 7, 13, 14, 45, 20, 61, 31, 9, 16, 7, 18, 45, 17, 23, 10, 71, 45, 39

Offset: 1

Author

Michel Lagneau, May 02 2014

Keywords

• nonn

Comments

Lambda(n) is the Carmichael lambda function(A002322).

It is highly probable that a solution exists for each n>0.

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, ...

Examples

			a(29) = 7 because lambda(29+7) = lambda(7) = 6.
		

Links

• Michel Lagneau, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002322, A007015, A173695.

Programs

Maple

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:

Mathematica

klambda[n_]:=Module[{k=1}, While[CarmichaelLambda[n+k]!= CarmichaelLambda [k], k++]; k]; Array[klambda, 70]