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A321536
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Write n in base 10, lengthen all the runs of successive identical digits by 1.
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3
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0, 11, 22, 33, 44, 55, 66, 77, 88, 99, 1100, 111, 1122, 1133, 1144, 1155, 1166, 1177, 1188, 1199, 2200, 2211, 222, 2233, 2244, 2255, 2266, 2277, 2288, 2299, 3300, 3311, 3322, 333, 3344, 3355, 3366, 3377, 3388, 3399, 4400, 4411, 4422, 4433, 444, 4455, 4466
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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COMMENTS
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LINKS
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EXAMPLE
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10 -> 1100, so a(10)=1100; 11->111, so a(11)=111.
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MATHEMATICA
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a[n_] := FromDigits@ Flatten[ Append[ #, Last@#] & /@ Split@ IntegerDigits[ n]]; a /@ Range[0, 46] (* Giovanni Resta, Nov 13 2018 *)
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PROG
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(Python)
from re import split
return int(''.join(d+d[0] for d in split('(0+)|(1+)|(2+)|(3+)|(4+)|(5+)|(6+)|(7+)|(8+)|(9+)', str(n)) if d != '' and d != None)) # Chai Wah Wu, Nov 13 2018
(PARI) a(n)={my(v=digits(n)); my(L=List()); for(i=1, #v, my(t=v[i]); if(i==1 || t<>v[i-1], listput(L, t)); listput(L, t)); fromdigits(Vec(L))} \\ Andrew Howroyd, Nov 13 2018
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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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EXTENSIONS
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STATUS
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approved
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