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A020333 Numbers n such that base 5 representation is the juxtaposition of two identical strings. 1
6, 12, 18, 24, 130, 156, 182, 208, 234, 260, 286, 312, 338, 364, 390, 416, 442, 468, 494, 520, 546, 572, 598, 624, 3150, 3276, 3402, 3528, 3654, 3780, 3906, 4032, 4158, 4284, 4410, 4536, 4662, 4788, 4914, 5040, 5166, 5292, 5418, 5544, 5670, 5796, 5922, 6048 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

tis5Q[n_]:=Module[{idn=IntegerDigits[n, 5], len}, len=Length[idn]; EvenQ[len] && Take[idn, len/2]==Take[idn, -len/2]]; Select[Range[6500], tis5Q]  (* or *) Flatten[Table[FromDigits[#, 5]&/@Select[(Flatten[{#, #}]&/@Tuples[ Range[ 0, 4], n]), #[[1]]!=0&], {n, 3}]] (* The second program is significantly faster than the first. *) (* Harvey P. Dale, Apr 08 2013 *)

CROSSREFS

Sequence in context: A073455 A279894 A209309 * A044831 A033003 A108592

Adjacent sequences:  A020330 A020331 A020332 * A020334 A020335 A020336

KEYWORD

nonn,base

AUTHOR

David W. Wilson, Melia Aldridge, ma38(AT)spruce.evansville.edu

STATUS

approved

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Last modified March 27 16:36 EDT 2017. Contains 284177 sequences.