A115669 Numbers the reversal of whose square is a brilliant number (A078972).

2, 3, 11, 13, 20, 30, 31, 59, 61, 101, 110, 112, 113, 128, 130, 131, 178, 200, 300, 301, 307, 310, 311, 388, 590, 599, 610, 839, 854, 875, 949, 989, 1003, 1010, 1021, 1031, 1100, 1102, 1103, 1105, 1112, 1120, 1124, 1130, 1175, 1201, 1216, 1280, 1300

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

3481=59^2 is a square and 1843=19*97 is brilliant.

Mathematica

sbnQ[n_]:=Module[{fi=FactorInteger[IntegerReverse[n^2]]}, (Length[fi]==1 && fi[[1, 2]]==2)||(Length[fi]==2&&fi[[All, 2]]=={1, 1})&&Length[Union[ IntegerLength[ fi[[All, 1]]]]]==1]; Select[Range[1300], sbnQ] (* Harvey P. Dale, Mar 23 2018 *)

Crossrefs

Cf. A078972, A115667, A115668.

Sequence in context: A038967 A001916 A089151 * A036956 A076503 A004678

Adjacent sequences: A115666 A115667 A115668 * A115670 A115671 A115672

Keyword

nonn,base

Author

Giovanni Resta, Jan 31 2006

Status

approved