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A276000 Least k such that n! divides phi(k!) (k > 0). 1
1, 3, 6, 6, 10, 10, 14, 14, 14, 14, 22, 22, 26, 26, 26, 26, 34, 34, 38, 38, 38, 38, 46, 46, 46, 46, 46, 46, 58, 58, 62, 62, 62, 62, 62, 62, 74, 74, 74, 74, 82, 82, 86, 86, 86, 86, 94, 94, 94, 94, 94, 94, 106, 106, 106, 106, 106, 106, 118, 118, 122, 122, 122, 122 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = 2*A007917(n) for n>2. - Andrey Zabolotskiy, Aug 16 2016
EXAMPLE
a(2) = 3 because phi(3!) is divisible by 2!.
MAPLE
N:= 100: # for a(1)..a(N)
V:= Vector(N): n:= 0:
for k from 1 while n < N do
r:= numtheory:-phi(k!);
for i from n+1 to N while r mod (i!) = 0 do
V[i]:= k; n:= i;
od;
od:
convert(V, list); # Robert Israel, Apr 24 2020
MATHEMATICA
Array[Block[{k = 1}, While[Mod[EulerPhi[k!], #!] != 0, k++]; k] &, 64] (* Michael De Vlieger, Apr 24 2020 *)
PROG
(PARI) a(n) = {my(k = 1); while(eulerphi(k!) % n!, k++); k; }
CROSSREFS
Sequence in context: A111652 A159787 A184161 * A333616 A316563 A349212
KEYWORD
nonn
AUTHOR
Altug Alkan, Aug 16 2016
STATUS
approved

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Last modified April 21 01:36 EDT 2024. Contains 371850 sequences. (Running on oeis4.)