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A162572 Decimal numbers n which, when converted to a lower number base, show the reversed digits of n. 0
1, 2, 3, 4, 5, 6, 7, 8, 13, 23, 46, 445, 2116, 15226, 313725, 1527465, 3454446, 2426472326, 3066511287, 102461381175475216 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

All entries lack the digit 9, because this digit is absent in the representations in bases 2 to 9.

The sequence is finite because for every n > 10^22 the representation of n in a base b < 10 has more digits than the representation of n in base 10. a(20) is the last term. - Giovanni Resta, Aug 13 2019

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

13 is 31 in base 4. 23 is 32 in base 7. 46 is 64 in base 7.

801 is a not a term since it is 1080 in base 9, so with an extra 0.

PROG

(PARI) isok(n) = {my(d = digits(n)); for (b=2, 9, my(rd = Vecrev(digits(n, b))); if ((#rd == #d) && fromdigits(rd) == n, return (b)); ); } \\ Michel Marcus, Aug 05 2019

CROSSREFS

Cf. A034294, A090144. - R. J. Mathar, Jul 17 2009

Sequence in context: A200374 A033080 A090144 * A250476 A222260 A032991

Adjacent sequences:  A162569 A162570 A162571 * A162573 A162574 A162575

KEYWORD

nonn,base,fini,full

AUTHOR

Claudio Meller, Jul 06 2009

EXTENSIONS

Keyword:base, single-digit numbers and 313725 added by R. J. Mathar, Jul 17 2009

a(16)-a(17) from Michel Marcus, Aug 05 2019

a(18)-a(19) from Giovanni Resta, Aug 06 2019

a(20) from Giovanni Resta, Aug 13 2019

STATUS

approved

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Last modified August 12 08:51 EDT 2020. Contains 336438 sequences. (Running on oeis4.)