A116006 n*phi(n)*phi(phi(n)) is a triangular number.

1, 3, 42, 77, 1517, 4238484

Offset

1,2

Links

Table of n, a(n) for n=1..6.

Example

1517*phi(1517)*phi(phi(1517))=T(40959).

Crossrefs

Cf. A116002.

Sequence in context: A055755 A249046 A237661 * A079826 A112291 A063040

Adjacent sequences: A116003 A116004 A116005 * A116007 A116008 A116009

Keyword

nonn

Author

Giovanni Resta, Feb 13 2006

Status

approved