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A071687 Non-palindromic numbers such that either x=q1.Rev[x] or Rev[x]=q2.x, where R[x]=A004086[x] and q1 or q2 are integers not divisible by 10. 2
510, 540, 810, 1089, 2100, 2178, 4200, 5200, 5610, 5700, 5940, 6300, 8400, 8712, 8910, 9801, 10989, 21978, 23100, 27000, 46200, 51510, 52200, 52800, 54540, 56610, 57200, 59940, 65340, 69300, 81810, 87912, 89910, 98901, 109989, 212100, 217800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..37.

FORMULA

q=Max[n/Rev[n], Rev[n]/n]=10m+r integer, where r>0, q>1.

EXAMPLE

Includes special cases of A071685. Examples represented by {n, Rev[n], integer-quotient} triples: {1089, 9801, 9}, {87912, 21979, 4}, {5610, 165, 34}, {610000, 16, 38125}, etc.

MATHEMATICA

nd[x_, y_] := 10*x+y tn[x_] := Fold[nd, 0, x] ed[x_] := IntegerDigits[x] red[x_] := Reverse[ed[x]] Do[s=Mod[ma=Max[{n, tn[red[n]]}], mi=Min[{n, r=tn[red[n]]}]]; If[Equal[s, 0]&&!Equal[n, r] &&!Equal[Mod[ma/mi, 10], 0], Print[{n, r, Max[r/n, n/r]}]], {n, 1, 1000000}]

CROSSREFS

Cf. A071685, A004046, A055483, A069554.

Sequence in context: A126582 A062905 A062914 * A048254 A303994 A249551

Adjacent sequences:  A071684 A071685 A071686 * A071688 A071689 A071690

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Jun 03 2002

STATUS

approved

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Last modified October 21 21:46 EDT 2019. Contains 328315 sequences. (Running on oeis4.)