|
|
A173614
|
|
a(n) = lcm_{p is prime and divisor of n} p-1.
|
|
6
|
|
|
1, 2, 1, 4, 2, 6, 1, 2, 4, 10, 2, 12, 6, 4, 1, 16, 2, 18, 4, 6, 10, 22, 2, 4, 12, 2, 6, 28, 4, 30, 1, 10, 16, 12, 2, 36, 18, 12, 4, 40, 6, 42, 10, 4, 22, 46, 2, 6, 4, 16, 12, 52, 2, 20, 6, 18, 28, 58, 4, 60, 30, 6, 1, 12, 10, 66, 16, 22, 12, 70, 2, 72, 36, 4, 18, 30, 12, 78, 4, 2, 40, 82, 6
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
2,2
|
|
COMMENTS
|
The function psi(n) in the paper by Carlip et al. - R. J. Mathar, Aug 22 2012
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
1425 = 3*5^2*19 => a(1425) = lcm(2,4,18) = 36.
|
|
MATHEMATICA
|
a[n_] := {aux = 1; fa = FactorInteger[n]; len = Length[fa]; grau = Table[fa[[s]][[1]] - 1, {s, len}]; Do[aux = LCM[aux, grau[[i]]], {i, len}]; aux}[[1]]; Table[a[n], {n, 2, 40}]
|
|
PROG
|
(PARI) a(n)=lcm(apply(p->p-1, factor(n)[, 1])) \\ Andrew Howroyd, Aug 06 2018
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|