A321536 Write n in base 10, lengthen all the runs of successive identical digits by 1.

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

Offset

0,2

Comments

A321537(a(n)) = n. Compare A321538.

Links

Giovanni Resta, Table of n, a(n) for n = 0..10000

Example

10 -> 1100, so a(10)=1100; 11->111, so a(11)=111.

Mathematica

a[n_] := FromDigits@ Flatten[ Append[ #, Last@#] & /@ Split@ IntegerDigits[ n]]; a /@ Range[0, 46] (* Giovanni Resta, Nov 13 2018 *)

Prog

(Python)
from re import split
def A321536(n):
    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

Crossrefs

A base-10 analog of A175046.

Cf. A321537, A321538.

Sequence in context: A280826 A020338 A052191 * A110732 A044836 A338754

Adjacent sequences: A321533 A321534 A321535 * A321537 A321538 A321539

Keyword

nonn,base,easy

Author

N. J. A. Sloane, Nov 13 2018

Extensions

More terms from Giovanni Resta, Nov 13 2018

Status

approved