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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A268721 Convolution of A006068 (inverse of Gray code) with itself: a(n) = Sum_{k=1..n+1} A006068(k) * A006068(1+n-k). 3
0, 1, 6, 13, 26, 58, 72, 107, 160, 230, 286, 440, 558, 599, 696, 851, 1032, 1298, 1510, 1826, 2122, 2353, 2624, 3294, 3884, 4335, 4870, 5001, 5242, 5722, 6048, 6699, 7424, 8226, 8990, 10166, 11226, 12069, 13048, 14384, 15664, 16885, 18134, 19071, 20094, 21276, 22360, 25150, 27788, 30091, 32582, 34343, 36262 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..1023

FORMULA

a(n) = Sum_{k=1..n+1} A006068(k) * A006068(1+n-k).

PROG

(Scheme)

(define A268721 (CONVOLVE 1 A006068 A006068)) ;; This version requires Antti Karttunen's IntSeq-library.

;; More stand-alone version:

(define (A268721 n) (add (lambda (k) (* (A006068 k) (A006068 (- (+ n 1) k)))) 1 (+ n 1)))

(define (add intfun lowlim uplim) (let sumloop ((i lowlim) (res 0)) (cond ((> i uplim) res) (else (sumloop (1+ i) (+ res (intfun i)))))))

CROSSREFS

Antidiagonal sums of array A268724.

Cf. A006068

Sequence in context: A081395 A343007 A192762 * A183337 A301687 A173559

Adjacent sequences:  A268718 A268719 A268720 * A268722 A268723 A268724

KEYWORD

nonn

AUTHOR

Antti Karttunen, Feb 13 2016

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 July 29 13:28 EDT 2021. Contains 346346 sequences. (Running on oeis4.)