|
|
A306896
|
|
a(n) = Sum_{d|n} (2^d + 2*(-1)^d)*phi(n/d).
|
|
5
|
|
|
0, 6, 6, 24, 30, 84, 126, 288, 522, 1080, 2046, 4224, 8190, 16548, 32850, 65856, 131070, 262836, 524286, 1049760, 2097438, 4196412, 8388606, 16782048, 33554550, 67117128, 134218782, 268452240, 536870910, 1073777040, 2147483646, 4295033472, 8589938742, 17180000352, 34359739050
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
MAPLE
|
|
|
MATHEMATICA
|
Table[DivisorSum[n, (2^# + 2 (-1)^#) EulerPhi[n/#] &], {n, 35}] (* Michael De Vlieger, Mar 18 2019 *)
|
|
PROG
|
(PARI) a(n) = sumdiv(n, d, (2^d + 2*(-1)^d)*eulerphi(n/d)); \\ Michel Marcus, Mar 16 2019
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|