A099144 - OEIS

A099144

Numbers n such that the equation S(k) = S(n+k) has no solutions for k <= n, where S is the Kempner function A002034.

1, 2, 6, 24, 48, 120, 240, 720

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OFFSET

1,2

COMMENTS

No other n < 10^6. Note that n is a factorial or twice a factorial. For n = 1 and 6, there is no known k such that S(k) = S(n+k). For n = 2, 24, 48, 120, 240 and 720, the least k is respectively 16, 48, 10192, 240, 3600 and 3888.

LINKS

Table of n, a(n) for n=1..8.

Eric Weisstein's World of Mathematics, Smarandache Function

MATHEMATICA

(*See A002034 for the Kempner function*) a=Table[Kempner[i], {i, 2000}]; lst={}; Do[i=1; While[i<=n&&a[[i]] != a[[i+n]], i++ ]; If[i>n, AppendTo[lst, n]], {n, 1000}]; lst

CROSSREFS

Cf. A099143 (least k such that S(k) = S(k+n)).

Sequence in context: A004306 A092485 A113904 * A354216 A189851 A189563

Adjacent sequences: A099141 A099142 A099143 * A099145 A099146 A099147

KEYWORD

nonn

AUTHOR

T. D. Noe, Sep 30 2004

STATUS

approved