login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A284320 Expansion of Product_{k>=0} (1 - x^(5*k+3)) in powers of x. 3
1, 0, 0, -1, 0, 0, 0, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 2, 0, -1, -1, 0, 2, 0, -1, -1, 0, 3, 0, -1, -2, 0, 3, 0, -1, -3, 0, 4, 1, -1, -4, 0, 4, 1, -1, -5, 0, 5, 2, -1, -7, 0, 5, 3, -1, -8, 0, 6, 5, -1, -10, -1, 6, 6, -1, -12, -1, 7, 9, -1, -14, -2, 7, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,22

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = -(1/n)*Sum_{k=1..n} A284281(k)*a(n-k), a(0) = 1.

MATHEMATICA

CoefficientList[Series[Product[1 - x^(5k + 3), {k, 0, 100}], {x, 0, 100}], x] (* Indranil Ghosh, Mar 25 2017 *) (* or *)

a[0]=1; a[n_]:=a[n]= -(1/n) Sum[ a[n-k] DivisorSum[k, # &, Mod[#, 5] == 3 &], {k, n}]; a /@ Range[0, 100] (* Giovanni Resta, Mar 25 2017 *)

PROG

(PARI) Vec(prod(k=0, 100, 1 - x^(5*k + 3)) + O(x^101)) \\ Indranil Ghosh, Mar 25 2017

CROSSREFS

Cf. Product_{k>=0} (1 - x^(5*k+m)): A284314 (m=1), A284319 (m=2), this sequence (m=3), A284317 (m=4).

Cf. A281271, A284281.

Sequence in context: A116799 A057556 A112761 * A281271 A284319 A281272

Adjacent sequences:  A284317 A284318 A284319 * A284321 A284322 A284323

KEYWORD

sign

AUTHOR

Seiichi Manyama, Mar 25 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 20 22:44 EDT 2019. Contains 328291 sequences. (Running on oeis4.)