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A080161
Indices of Wonderful Demlo numbers A002477 whose digit sums are squares.
4
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
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