The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A280654 a(n) = (n!)^2 * Sum_{k=1..n} A008836(k)/k^2. 2
 1, 3, 23, 404, 9524, 357264, 16987536, 1061800704, 87631559424, 8894837836800, 1063107188812800, 151494084266803200, 25373057708287180800, 5011895098867920076800, 1135276451701834014720000, 292340783888393707192320000, 84048723407048386326036480000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Daniel Suteu, Table of n, a(n) for n = 1..100 Wikipedia, Liouville function. FORMULA Limit_{n->infinity} a(n)/(n!)^2 = zeta(4)/zeta(2) = Pi^2/15. MATHEMATICA Table[(n!)^2 * Sum[(-1)^PrimeOmega[k]/k^2, {k, n}], {n, 20}] (* Indranil Ghosh, Apr 13 2017 *) PROG (PARI) a(n) = (n!)^2 * sum(k=1, n, (-1)^bigomega(k)/k^2); CROSSREFS Cf. A001044, A008836, A182448 (Pi^2/15). Sequence in context: A114601 A178315 A210910 * A118195 A055326 A271851 Adjacent sequences: A280651 A280652 A280653 * A280655 A280656 A280657 KEYWORD nonn AUTHOR Daniel Suteu, Apr 12 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 10 19:25 EDT 2024. Contains 375058 sequences. (Running on oeis4.)