A197952 Numbers n such that sigma(phi(n))/sigma(n) = 5.

1033474069, 1604277377, 2741806637, 9941342981, 14754456491, 14859359791, 15887724883, 16990353761, 17266051069, 20892536447, 21776951239, 24435763193, 25165559143, 32325726313, 38313868379, 38580669727, 38856433193, 47906215417, 49094416289, 56237053007

Offset

1,1

Links

Table of n, a(n) for n=1..20.

Example

sigma(phi(25165559143))/sigma(25165559143) = 127671828480/25534365696 = 5.

Prog

(PARI) for(n=1033474069, 3*10^10, if(sigma(eulerphi(n))/sigma(n)==5, print1(n, ", ")))

Crossrefs

Cf. A033631, A066831, A067382, A067383, A067384, A067385.

Sequence in context: A359342 A268312 A035124 * A321066 A222531 A167476

Adjacent sequences: A197949 A197950 A197951 * A197953 A197954 A197955

Keyword

nonn

Author

Donovan Johnson, Oct 19 2011

Extensions

a(14)-a(20) from Donovan Johnson, Nov 11 2011

Status

approved