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A254378 Run lengths of A228495 (Characteristic function of the odd odious numbers). 3
1, 1, 5, 1, 3, 1, 1, 1, 5, 1, 1, 1, 3, 1, 5, 1, 3, 1, 1, 1, 3, 1, 5, 1, 1, 1, 5, 1, 3, 1, 1, 1, 5, 1, 1, 1, 3, 1, 5, 1, 1, 1, 5, 1, 3, 1, 1, 1, 3, 1, 5, 1, 3, 1, 1, 1, 5, 1, 1, 1, 3, 1, 5, 1, 3, 1, 1, 1, 3, 1, 5, 1, 1, 1, 5, 1, 3, 1, 1, 1, 3, 1, 5, 1, 3, 1, 1, 1, 5, 1, 1, 1, 3, 1, 5, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Also run lengths of A254377 = 1-A228495(n).
LINKS
EXAMPLE
A228495 begins 0,1,0,0,0,0,0,1,0, hence this sequence begins 1,1,5,1.
MATHEMATICA
Length /@ Split[Table[If[OddQ[n] && OddQ[DigitCount[n, 2, 1]], 1, 0], {n, 0, 200}]] (* Amiram Eldar, Aug 07 2023 *)
PROG
(PARI)
up_to = 65537;
A254378lista(up_to) = { my(v=vector(up_to), r=1, n=0, i=1, pb=0, b); while(n<up_to, b = (hammingweight(i)%2)*(i%2); if(b==pb, r++, n++; v[n] = r; r = 1; pb = b); i++); (v); }; \\ Antti Karttunen, Oct 01 2018
v254378 = A254378lista(up_to);
A254378(n) = v254378[n]; \\ Antti Karttunen, Oct 01 2018
(Python)
from itertools import count, islice, groupby
def A254378_gen(): # generator of terms
return (len(list(g)) for k, g in groupby(n.bit_count()&1&n for n in count(0)))
A254378_list = list(islice(A254378_gen(), 20)) # Chai Wah Wu, Mar 09 2023
CROSSREFS
Sequence in context: A091384 A011305 A348317 * A134568 A198798 A229181
KEYWORD
nonn,base
AUTHOR
Jeremy Gardiner, Jan 29 2015
STATUS
approved

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Last modified June 24 13:56 EDT 2024. Contains 373679 sequences. (Running on oeis4.)