

A074845


Numbers n such that S(n) = largest difference between consecutive divisors of n (ordered by size), where S(n) is the Kempner function (A002034).


4



6, 8, 9, 10, 14, 22, 26, 34, 38, 46, 58, 62, 74, 82, 86, 94, 106, 118, 122, 134, 142, 146, 158, 166, 178, 194, 202, 206, 214, 218, 226, 254, 262, 274, 278, 298, 302, 314, 326, 334, 346, 358, 362, 382, 386, 394, 398, 422, 446, 454, 458, 466, 478, 482, 502, 514
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OFFSET

1,1


COMMENTS

It appears that terms > 6 are simply given by: composite n such that n^2 doesn't divide A000254(n).  Benoit Cloitre, Mar 09 2004
It appears that A011776(a(n)) = 2.  Gionata Neri, Jul 31 2017
It appears that this sequence consists of the numbers n such that A045763(n) > 0 and n does not divide A070251(n).  Isaac Saffold, Jun 01 2018


LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..670 (a(n) < 10^4, from bfile at A002034).


MATHEMATICA

Select[Range@ 514, Function[n, Module[{m = 1}, While[! Divisible[m!, n], m++]; m] == Max@ Differences@ Divisors@ n]] (* Michael De Vlieger, Jul 31 2017 *)


PROG

(PARI) K(n) = my(s=1); while(s!%n>0, s++); s;
dd(n) = my(vd=divisors(n)); vecmax(vector(#vd1, k, vd[k+1]  vd[k]));
isok(n) = K(n) == dd(n); \\ Michel Marcus, Aug 03 2017


CROSSREFS

Cf. A002034, A060681.
Sequence in context: A161186 A102106 A175821 * A001746 A025070 A123704
Adjacent sequences: A074842 A074843 A074844 * A074846 A074847 A074848


KEYWORD

easy,nonn


AUTHOR

Jason Earls, Sep 10 2002


STATUS

approved



