login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A033265
Number of i such that d(i) >= d(i-1), where Sum_{i=0..m} d(i)*2^i is the base-2 representation of n.
9
0, 1, 1, 2, 1, 2, 2, 3, 2, 2, 2, 3, 2, 3, 3, 4, 3, 3, 3, 3, 2, 3, 3, 4, 3, 3, 3, 4, 3, 4, 4, 5, 4, 4, 4, 4, 3, 4, 4, 4, 3, 3, 3, 4, 3, 4, 4, 5, 4, 4, 4, 4, 3, 4, 4, 5, 4, 4, 4, 5, 4, 5, 5, 6, 5, 5, 5, 5, 4, 5, 5, 5, 4, 4, 4, 5, 4, 5, 5, 5, 4, 4, 4, 4, 3, 4, 4, 5, 4, 4
OFFSET
1,4
FORMULA
From Ralf Stephan, Oct 05 2003: (Start)
a(0) = 0, a(2n) = a(n) + 1, a(2n+1) = a(n) + [n odd].
a(n) = A014081(n) + A023416(n).
G.f.: 1/(1-x) * Sum_{k>=0} (t^2 + t^3 + t^4)/((1+t)*(1+t^2)), t=x^2^k. (End)
a(n) = -1 + A297113(A005940(1+n)). - Antti Karttunen, Dec 30 2017
EXAMPLE
The base-2 representation of n=4 is 100 with d(0)=0, d(1)=0, d(2)=1. There are two rise-or-equal, one from d(0) to d(1) and one from d(1) to d(2), so a(4)=2. - R. J. Mathar, Oct 16 2015
MAPLE
A033265 := proc(n)
a := 0 ;
dgs := convert(n, base, 2);
for i from 2 to nops(dgs) do
if op(i, dgs)>=op(i-1, dgs) then
a := a+1 ;
end if;
end do:
a ;
end proc: # R. J. Mathar, Oct 16 2015
PROG
(PARI) A033265(n) = { my(i=0); while(n>1, if((n%4)!=1, i++); n >>= 1); (i); }; \\ Antti Karttunen, Aug 06 2023
CROSSREFS
KEYWORD
nonn,base,changed
EXTENSIONS
Sign in Name corrected by R. J. Mathar, Oct 16 2015
STATUS
approved