login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A227761 a(n) is the maximal difference between successive parts in the minimally runlength-encoded unordered partition of n (A227368(n)). 4
0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 1, 0, 2, 1, 0, 0, 1, 1, 1, 0, 1, 1, 2, 0, 0, 1, 1, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 2, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 2, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2, 0, 0, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,8

COMMENTS

After n=3, only composites may obtain value 0. (But not all of them do; see A227762.) The first nine n for which a(n)=2 are 7, 13, 23, 33, 47, 61, 79, 97, 119, of which all are primes except 33 and 119. Conjecture: these values are given by A227786.

Are there any terms larger than 2?

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..132

FORMULA

a(0) = a(1) = 0, and for n>1, a(n) = A043276(A163575(A227368(n))) - 1.

PROG

(Scheme)

(define (A227761 n) (if (< n 2) 0 (- (A043276 (A163575 (A227368 n))) 1)))

;; Alternative version which uses auxiliary functions DIFF and binexp_to_ascpart which can be found in the Program section of A129594:

(define (A227761v2 n) (if (< n 2) 0 (apply max (DIFF (binexp_to_ascpart (A227368 n))))))

CROSSREFS

A227762 gives the positions of zeros, in other words, such n that their minimally runlength-encoded partition consists of identical parts.

Cf. also A227368 (for the concept of minimally runlength-encoded unordered partition).

Sequence in context: A024153 A079127 A056674 * A037188 A276847 A271231

Adjacent sequences:  A227758 A227759 A227760 * A227762 A227763 A227764

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jul 26 2013

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 19 12:36 EST 2020. Contains 331049 sequences. (Running on oeis4.)