A080161 Indices of Wonderful Demlo numbers A002477 whose digit sums are squares.

1, 2, 3, 4, 5, 6, 7, 8, 9, 36, 51, 66, 81, 102, 123, 144, 225, 258, 291, 324, 363, 402, 441, 576, 593, 610, 627, 644, 661, 678, 695, 712, 729, 748, 767, 786, 805, 824, 843, 862, 881, 900, 1089, 1158, 1227, 1296, 1371, 1446, 1521, 1764, 1851, 1938, 2025

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

Cf. A080160, A080162, A002477, A080151, A108690.

Sequence in context: A276143 A064154 A316147 * A345405 A257554 A270393

Adjacent sequences: A080158 A080159 A080160 * A080162 A080163 A080164

Keyword

nonn,base

Author

Eric W. Weisstein, Jan 31 2003

Status

approved