|
|
A160620
|
|
a(n) = Sum_{d|n} phi(n/d)^2*2^d.
|
|
2
|
|
|
0, 2, 6, 16, 28, 64, 96, 200, 320, 616, 1152, 2248, 4304, 8480, 16728, 33152, 66048, 131584, 263160, 524936, 1050176, 2098240, 4196952, 8389576, 16782976, 33555744, 67117920, 134220712, 268453360, 536872480, 1073780352, 2147485448, 4295034880, 8589944384
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
|
|
MAPLE
|
if n =0 then
0;
else
add((numtheory[phi](n/d))^2*2^d, d=numtheory[divisors](n)) ;
end if ;
|
|
MATHEMATICA
|
a[n_]:= If[n<1, 0, Sum[EulerPhi[n/d]^2 * 2^d, {d, Divisors[n]}]]; Table[a[n], {n, 0, 50}] (* G. C. Greubel, May 06 2018 *)
|
|
PROG
|
(PARI) a(n) = if (n, sumdiv(n, d, eulerphi(n/d)^2*2^d), 0); \\ Michel Marcus, May 07 2018, Jun 22 2021
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|