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A321537 Write n in base 10, shorten all the runs of successive identical digits by 1. 3
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 2, 0 (list; graph; refs; listen; history; text; internal format)
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
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
A base-10 analog of A318921.
Sequence in context: A028706 A060175 A358480 * A218876 A028621 A226557
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Nov 13 2018
STATUS
approved

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Last modified March 29 03:51 EDT 2024. Contains 371264 sequences. (Running on oeis4.)