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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A371998 a(n) = A000166(floor(n/2)) if n is even otherwise A000240(floor((n + 1)/2)). 1
 1, 1, 0, 0, 1, 3, 2, 8, 9, 45, 44, 264, 265, 1855, 1854, 14832, 14833, 133497, 133496, 1334960, 1334961, 14684571, 14684570, 176214840, 176214841, 2290792933, 2290792932, 32071101048, 32071101049, 481066515735, 481066515734, 7697064251744, 7697064251745 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 LINKS Table of n, a(n) for n=0..32. MAPLE a := n -> if irem(n, 2) = 0 then A000166(iquo(n, 2)) else A000240(iquo(n+1, 2)) fi: seq(a(n), n = 0..32); PROG (Python) from functools import cache @cache def sf(n): if n == 0: return 1 return n * sf(n - 1) + (-1 if n % 2 else 1) def a(n): h, r = divmod(n, 2) return sf(h) * (h + 1) if r else sf(h) print([a(n) for n in range(33)]) CROSSREFS Cf. A000166, A000240. Sequence in context: A274181 A195055 A214683 * A363816 A060921 A163356 Adjacent sequences: A371995 A371996 A371997 * A371999 A372000 A372001 KEYWORD nonn AUTHOR Peter Luschny, Apr 25 2024 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 2 22:39 EDT 2024. Contains 374875 sequences. (Running on oeis4.)