OFFSET
0,23
COMMENTS
More than the usual number of terms are shown in order to reach some interesting terms.
All primes vanish except those in A050758.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 0..10000
EXAMPLE
22 -> 2, so a(22)=2 is the first term > 1.
10 in not reached until a(1100) = 10.
MAPLE
read("transforms"):
A321537 := proc(n)
local dgsin, dgsout, pos ;
dgsin := convert(n, base, 10) ;
dgsout := [] ;
for pos from 2 to nops(dgsin) do
if op(pos, dgsin) = op(pos-1, dgsin) then
dgsout := [op(pos, dgsin), op(dgsout)] ;
end if;
end do:
digcatL(dgsout) ;
end proc: # R. J. Mathar, Nov 14 2018
MATHEMATICA
Array[FromDigits[Join @@ Map[Most, Split@ IntegerDigits@ #]] &, 123] (* Michael De Vlieger, Nov 13 2018 *)
PROG
(Python)
from re import split
def A321537(n):
return int('0'+''.join(d[:-1] 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))); fromdigits(Vec(L))} \\ Andrew Howroyd, Nov 13 2018
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Nov 13 2018
STATUS
approved