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A072005 Smallest solution to gcd(k, reverse(k)) = 3^n. 7
1, 3, 9, 2889, 2899999989, 4899999987, 19899999972, 29898999693, 49989958299, 49999917897, 99884394999, 372797889885, 1989767716659, 2678052898989, 17902896898419, 137530987695297, 189281899170567, 368055404997498, 14048104419899757, 437893473401621955, 218264275944702783 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..20.

FORMULA

a(n) = A069554(3^n).

EXAMPLE

n=4: 3^4 = 81, a(4) = 2899999989 = 3*3*3*3*35802469, reverse(a(4)) = 2*3*3*3*3*61111111; gcd = 81 = 3^n.

CROSSREFS

Cf. A004086, A055483, A069554, A071686, A071686, A072021, A072050.

Sequence in context: A112725 A060712 A122463 * A060377 A255503 A027896

Adjacent sequences:  A072002 A072003 A072004 * A072006 A072007 A072008

KEYWORD

nonn,base

AUTHOR

Labos Elemer, Jun 04 2002

EXTENSIONS

a(15)-a(20) from Giovanni Resta, Oct 30 2019

STATUS

approved

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Last modified May 15 02:21 EDT 2021. Contains 343909 sequences. (Running on oeis4.)