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

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.

Sequence in context: A253261 A280587 A273372 * A053887 A119943 A001245

Adjacent sequences: A366076 A366077 A366078 * A366080 A366081 A366082

Keyword

nonn

Author

Stuart E Anderson, Sep 28 2023

Extensions

a(11)-a(12) from Michel Marcus, Sep 28 2023

a(13)-a(22) from Hugo Pfoertner, Sep 28 2023

Status

approved