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!)
A322205 a(n) = coefficient of x^(2*n)*y^n/n in Sum_{n>=1} -log(1 - (x^n + y^n)) for n >= 1. 4
1, 7, 31, 179, 1006, 6265, 38767, 245515, 1562368, 10017042, 64512251, 417238925, 2707475161, 17620153929, 114955811686, 751616795579, 4923689695592, 32308786002880, 212327989773919, 1397281521970074, 9206478467570842, 60727722789611357, 400978991944396343, 2650087221531556021, 17529515713716302906, 116043807648704288815, 768759815833955021344, 5096278545391603271517 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..28.

FORMULA

a(n) = A322200(2*n,n)/3.

EXAMPLE

G.f.: L(x) = x + 7*x^2/2 + 31*x^3/3 + 179*x^4/4 + 1006*x^5/5 + 6265*x^6/6 + 38767*x^7/7 + 245515*x^8/8 + 1562368*x^9/9 + 10017042*x^10/10 + 64512251*x^11/11 + 417238925*x^12/12 + ...

such that

exp( L(x) ) = 1 + x + 4*x^2 + 14*x^3 + 63*x^4 + 294*x^5 + 1526*x^6 + 8157*x^7 + 45332*x^8 + 257378*x^9 + 1489539*x^10 + 8744722*x^11 + 51965701*x^12 + ... + A322206(n)*x^n + ...

PROG

(PARI)

{L = sum(n=1, 81, -log(1 - (x^n + y^n) +O(x^81) +O(y^81)) ); }

{a(n) = polcoeff( n*polcoeff( L, 2*n, x), n, y)}

for(n=1, 35, print1( a(n), ", ") )

CROSSREFS

Cf. A322200, A322206.

Sequence in context: A264608 A208446 A172634 * A139151 A139060 A324621

Adjacent sequences:  A322202 A322203 A322204 * A322206 A322207 A322208

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Dec 01 2018

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 11 23:53 EDT 2020. Contains 335654 sequences. (Running on oeis4.)