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A066970 Integers of the form sum(i=1,m,phi(i)/gcd(m,i)). 1
1, 4, 20, 58, 178, 248, 880, 965, 2289, 2664, 4096, 3233, 7254, 15447, 30658, 35869, 49485, 102248, 116225, 272130, 247872, 322891, 407484, 521003, 444794, 929334, 1022620, 1653250, 1792704, 1859231, 2070655, 2906985, 3965654, 6952192, 10631022, 11049130 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..36.

MATHEMATICA

Select[Table[Sum[EulerPhi[i]/GCD[m, i], {i, m}], {m, 2000}], IntegerQ] (* Harvey P. Dale, Jun 05 2012 *)

PROG

(PARI) lista(nn) = {for (n = 1, nn, if (type(v = sum(i=1, n, eulerphi(i)/gcd(n, i))) == "t_INT", print1(v, ", ")); ); } \\ Michel Marcus, Nov 20 2013

CROSSREFS

Cf. A066969.

Sequence in context: A002492 A127920 A060122 * A196295 A196213 A196680

Adjacent sequences:  A066967 A066968 A066969 * A066971 A066972 A066973

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jan 26 2002

EXTENSIONS

More terms from Michel Marcus, Nov 20 2013

STATUS

approved

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Last modified October 20 21:32 EDT 2020. Contains 337910 sequences. (Running on oeis4.)