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A032827
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Numbers whose set of base-15 digits is {1,4}.
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1
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1, 4, 16, 19, 61, 64, 241, 244, 286, 289, 916, 919, 961, 964, 3616, 3619, 3661, 3664, 4291, 4294, 4336, 4339, 13741, 13744, 13786, 13789, 14416, 14419, 14461, 14464, 54241, 54244, 54286, 54289, 54916, 54919, 54961, 54964
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graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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a(1)=1, a(2)=4; a(n) = 15*a(floor(n/2))+1 for n odd, otherwise a(n) = 15*a(floor((n-1)/2))+4. - Bruno Berselli, May 28 2012
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MATHEMATICA
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Flatten[Table[FromDigits[#, 15]&/@Tuples[{1, 4}, n], {n, 5}]] (* Vincenzo Librandi, May 28 2012 *)
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PROG
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(Magma) [n: n in [1..60000] | Set(IntegerToSequence(n, 15)) subset {1, 4}]; // Vincenzo Librandi, May 28 2012
(Maxima) a[1]:1$ a[2]:4$ a[n]:= if oddp(n) then 15*a[floor(n/2)]+1 else 15*a[floor((n-1)/2)]+4$ makelist(a[n], n, 1, 38); /* Bruno Berselli, May 28 2012 */
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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