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A032917 Numbers having only digits 1 and 3 in their decimal representation. 8
1, 3, 11, 13, 31, 33, 111, 113, 131, 133, 311, 313, 331, 333, 1111, 1113, 1131, 1133, 1311, 1313, 1331, 1333, 3111, 3113, 3131, 3133, 3311, 3313, 3331, 3333, 11111, 11113, 11131, 11133, 11311, 11313, 11331, 11333, 13111, 13113 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers n such that product of digits of n is a power of 3. - Vincenzo Librandi Aug 19 2016

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Flatten[Table[FromDigits[#, 10]&/@Tuples[{1, 3}, n], {n, 5}]] (* Vincenzo Librandi, Jun 02 2012 *)

PROG

(MAGMA) [n: n in [1..14000] | Set(IntegerToSequence(n, 10)) subset {1, 3}]; // Vincenzo Librandi, Jun 02 2012

(PARI) for(n=1, 5, p=2*vector(n, i, 10^(n-i))~; forvec(d=vector(n, i, [1, 3]/2), print1(d*p, ", "))) \\ M. F. Hasler, Mar 10 2014

CROSSREFS

Sequence in context: A287348 A019374 A033680 * A006559 A023248 A199341

Adjacent sequences:  A032914 A032915 A032916 * A032918 A032919 A032920

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

EXTENSIONS

Definition reworded by M. F. Hasler, Mar 10 2014

STATUS

approved

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Last modified September 25 19:48 EDT 2017. Contains 292500 sequences.