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

Author

N. J. A. Sloane, Nov 13 2018

Keywords

• nonn
• base
• easy

Comments

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

Examples

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

Links

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

Crossrefs

A base-10 analog of A175046.

Cf. A321537, A321538.

Programs

Mathematica

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

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

Extensions

More terms from Giovanni Resta, Nov 13 2018