A366079 - OEIS

A366079

Perfect squares in A005728.

1, 81, 121, 361, 1352569, 2140369, 6416089, 9186961, 30261001, 108056025, 820765201, 2331248089, 170938421809, 8189950752481, 8870860603201, 33527956250889, 136943052939289, 149526943190641, 4953581020385761, 509672946670475329, 578899033007097609, 2043000477545048329

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

a(3) = 361 because A005728(34) = 361 and 361 is 19 squared.

PROG

(PARI) f(n)=1+sum(k=1, n, eulerphi(k)); \\ A005728

select(x->issquare(x), apply(f, [0..10^5])) \\ Michel Marcus, Sep 28 2023

CROSSREFS

Cf. A000290, A005728.