login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A293517 a(n) = A293518(n) - A293519(n); how many more surviving even nodes than surviving (but not bifurcating) odd nodes there are at generation n in the binary tree of persistently squarefree numbers. 6
0, 1, 1, 1, 1, 2, 1, 3, 4, 5, 9, 8, 10, 20, 17, 36, 32, 50, 66, 83, 118, 171, 219, 291, 410, 511, 730, 952, 1325, 1665, 2389, 3100, 4147, 5631, 7591, 10093, 13756, 18390, 24540, 33288, 44391, 60052, 80291, 108096, 145226, 194764, 262091, 352096, 473452, 635336, 854332, 1147668 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,6
COMMENTS
As long as there are at least as many surviving even than surviving (but not bifurcating) odd nodes at each generation in the tree of persistently squarefree numbers (see illustration in A293230), this sequence also stays nonnegative, and being also the first differences of A293441 guarantees its monotonicity. If A293441 is monotonic, then A293230 is also, which in turn implies also that A293430 has infinite number of terms and that there will be nonzero terms arbitrary far in A293233.
The surviving children of even vertices are all of the form 4k+1, while the surviving children (those without an odd sibling) of odd vertices are all of the form 4k+2.
LINKS
FORMULA
a(n) = A293518(n) - A293519(n).
a(n) = A293441(1+n) - A293441(n).
PROG
(Scheme) (define (A293517 n) (- (A293518 n) (A293519 n)))
CROSSREFS
First differences of A293441.
Cf. also A293428.
Sequence in context: A075379 A308000 A029636 * A122514 A130077 A080412
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 16 2017
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 20 03:21 EDT 2024. Contains 373512 sequences. (Running on oeis4.)