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A071686 Smallest solution to GCD(x,Rev(x)) = 2^n. 10
2, 4, 8, 2192, 21920, 291008, 610688, 2112256, 2131456, 2937856, 25329664, 230465536, 694018048, 2344321024, 4688642048, 2112421888, 65012891648, 650128916480, 4494196736, 63769149440, 637691494400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..21.

FORMULA

a(n) = A069554(2^n).

MATHEMATICA

nd[x_, y_] := 10*x+y tn[x_] := Fold[nd, 0, x] ed[x_] := IntegerDigits[x] red[x_] := Reverse[IntegerDigits[x]] nd[x_, y_] := 10*x+y tn[x_] := Fold[nd, 0, x] ed[x_] := IntegerDigits[x] Table[fl=0; Do[s=GCD[(2^g)*m, u=tn[red[(2^g)*m]]]; If[Equal[s, 2^g]&&Equal[fl, 0], Print[(2^g)*m}]; fl=1], {n, 1, 3000000}], {g, 1, 21}]

CROSSREFS

Cf. A004086, A055483, A069554.

Sequence in context: A067499 A135212 A012456 * A296742 A103097 A062286

Adjacent sequences:  A071683 A071684 A071685 * A071687 A071688 A071689

KEYWORD

nonn,base

AUTHOR

Labos Elemer, Jun 03 2002

STATUS

approved

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Last modified October 14 00:10 EDT 2019. Contains 327990 sequences. (Running on oeis4.)