A015764 Numbers n such that phi(n) | sigma_6(n).

1, 2, 3, 6, 22, 33, 66, 262, 750, 786, 8646, 56946, 222386, 626406, 667158, 737286, 1223123, 2446246, 2939046, 3669369, 6804006, 7338738, 27798250, 31684246, 41697375, 44970486, 53817126, 62128086, 76745867, 83394750, 95052738, 139991987, 153491734, 174684203

Offset

1,2

Comments

sigma_6(n) is the sum of the 6th powers of the divisors of n.

Links

Table of n, a(n) for n=1..34.

Maple

with(numtheory): A015764:=n->`if`(sigma[6](n) mod phi(n) = 0, n, NULL): seq(A015764(n), n=1..10^5); # Wesley Ivan Hurt, Mar 10 2015

Mathematica

Select[Range[10^5], Divisible[DivisorSigma[6, #], EulerPhi[#]] &] (* Amiram Eldar, Jan 20 2019 *)

Crossrefs

Cf. A000010 (phi(n)), A013954 (sigma_6(n)).

Cf. A020492, A015759, A015761, A015762, A015763, A015765, A015766, A015767, A015768, A015769, A015770, A015771, A015773, A015774, A094470.

Sequence in context: A015773 A015768 A094470 * A015759 A260562 A173249

Adjacent sequences: A015761 A015762 A015763 * A015765 A015766 A015767

Keyword

nonn

Author

Robert G. Wilson v

Extensions

More terms from Labos Elemer, May 03 2002

a(23)-a(34) from Amiram Eldar, Jan 20 2019

Status

approved