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A241928 a(n) = smallest k such that lambda(n+k) = lambda(k). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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, ...

LINKS

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

EXAMPLE

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

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]

CROSSREFS

Cf. A002322, A007015, A173695.

Sequence in context: A168309 A103947 A178038 * A111048 A016700 A088910

Adjacent sequences:  A241925 A241926 A241927 * A241929 A241930 A241931

KEYWORD

nonn

AUTHOR

Michel Lagneau, May 02 2014

STATUS

approved

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Last modified February 18 05:48 EST 2018. Contains 299298 sequences. (Running on oeis4.)