This site is supported by donations to The OEIS Foundation.

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!)
 A032278 Number of ways to partition n elements into pie slices each with at least 2 elements allowing the pie to be turned over. 2
 0, 1, 1, 2, 2, 4, 4, 7, 8, 13, 15, 25, 30, 48, 63, 98, 132, 208, 290, 454, 656, 1021, 1509, 2358, 3544, 5535, 8441, 13200, 20318, 31835, 49352, 77435, 120710, 189673, 296853, 467159, 733362, 1155646, 1818593, 2869377, 4524080 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS A134681(n) = A055642(a(n)). - Reinhard Zumkeller, Nov 06 2007 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..500 C. G. Bower, Transforms (2) FORMULA "DIK" (bracelet, indistinct, unlabeled) transform of 0, 1, 1, 1, ... G.f.: (x^2/((1 - x)*(1 - x^2 - x^4)) + Sum_{d>0} phi(d)*log((1 - x^d)/(1 - x^d - x^(2*d)))/d)/2. - Andrew Howroyd, Jun 20 2018 PROG (PARI) seq(n)={Vec(x^2/((1-x)*(1-x^2-x^4)) + sum(d=1, n, eulerphi(d)/d*log((1-x^d)/(1-x^d-x^(2*d)) + O(x*x^n))), -n)/2} \\ Andrew Howroyd, Jun 20 2018 CROSSREFS Cf. A000005, A027750. Sequence in context: A035554 A183567 A222710 * A222738 A005308 A151532 Adjacent sequences:  A032275 A032276 A032277 * A032279 A032280 A032281 KEYWORD nonn AUTHOR 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.

Last modified January 19 21:52 EST 2019. Contains 319310 sequences. (Running on oeis4.)