OFFSET
1,2
COMMENTS
The numbers 9*n^2 (A016766), with n > 0, are in this sequence. - Enrique Pérez Herrero, Sep 26 2020
LINKS
Jeppe Stig Nielsen, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Demlo Number
MATHEMATICA
A080151[n_] := (9^2)*(n/9 - FractionalPart[n/9] + FractionalPart[n/9]^2)
Select[Range[10000], IntegerQ[Sqrt[A080151[#]]] &]
(* Enrique Pérez Herrero, Sep 26 2020 *)
PROG
(PARI) for(k=1, 10^5, issquare((k\9)*81+(k%9)^2)&&print1(k, ", ")) \\ Jeppe Stig Nielsen, May 27 2023
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric W. Weisstein, Jan 31 2003
STATUS
approved