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A181540 a(n) = Sum_{k=0..n} gcd(n,k)*phi(k). 2
0, 1, 3, 8, 13, 26, 29, 54, 59, 84, 93, 142, 139, 202, 195, 244, 259, 352, 327, 444, 433, 508, 505, 656, 639, 776, 719, 866, 889, 1054, 1057, 1208, 1151, 1332, 1255, 1624, 1575, 1728, 1579, 1886, 2011, 2130, 2159, 2348, 2329, 2716, 2329 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Row sums of triangle A181538.
LINKS
MAPLE
A181540 := n -> add(igcd(n, k)*numtheory[phi](k), k=0..n);
MATHEMATICA
Table[Sum[GCD[n, k]EulerPhi[k], {k, 0, n}], {n, 0, 50}] (* Harvey P. Dale, Jul 12 2020 *)
PROG
(PARI) a(n) = sum(k=1, n, gcd(n, k)*eulerphi(k)); \\ Michel Marcus, May 18 2018
CROSSREFS
Cf. A181538.
Sequence in context: A051838 A076792 A146939 * A059028 A066809 A009848
KEYWORD
nonn
AUTHOR
Peter Luschny, Oct 29 2010
STATUS
approved

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Last modified March 2 04:55 EST 2024. Contains 370460 sequences. (Running on oeis4.)