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URL: https://oeis.org/A274795

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A274795
Least k such that d(k*n) = d(n!) (d = A000005).
0
1, 1, 2, 6, 24, 120, 720, 3465, 18480, 194040, 2293200, 19219200, 301593600, 1163962800, 6518191680, 20078358300, 548021073600, 42643458457600, 1090774779494400, 15198128594288640, 136285012131840000, 55135902013920000, 1951331488666560000, 9736473836722913280000
OFFSET
1,3
EXAMPLE
a(8) = 3465 because A000005(3465*8) = A000005(8!).
MATHEMATICA
dec[v_, w_] := If[v == 1, Sow@w, dec[v/#, Append[w, #]] & /@ Select[Rest@ Divisors@ v, # <= w[[-1]] &]]; mul[n_] := Reap[dec[n/#, {#}] & /@ Rest@ Divisors@n][[2, 1]]; ev[e_] := Times @@ (Prime[ Range@ Length@ e]^e); a[n_] := If[n == 1, 1, Min[ev /@ (mul[ DivisorSigma[0, n!]] - 1)]/n]; Array[a, 24] (* Giovanni Resta, Jul 29 2016 *)
CROSSREFS
Sequence in context: A189853 A189857 A189860 * A174702 A173846 A154654
KEYWORD
nonn
AUTHOR
Altug Alkan, Jul 29 2016
EXTENSIONS
a(12)-a(24) from Giovanni Resta, Jul 29 2016
STATUS
approved