The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A014454 Sum_{1<=k
 0, 1, 2, 5, 6, 21, 22, 73, 210, 1693, 1694, 2097, 2098, 12997, 21468, 174169, 174170, 1986237, 1986238, 10178833, 16875654, 246551437, 246551438, 2032266537, 3767596738, 45445808989, 260705796192, 2932954933753, 2932954933754, 5496591783573, 5496591783574 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..500 EXAMPLE a(5) = gcd(1!,5!)+gcd(2!,3*4*5)+gcd(3!,4*5)+gcd(4!,5)=1+2+2+1 = 6. PROG (PARI) a(n) = sum(k=1, n-1, gcd(k!, n!/k!)); \\ Michel Marcus, Aug 04 2013 (Haskell) a014454 n = sum \$ zipWith gcd kfs \$ map (div nf) kfs where (nf:kfs) = reverse \$ a166350_row n -- Reinhard Zumkeller, Nov 11 2013 CROSSREFS Cf. A000142. Cf. A166350. Sequence in context: A248719 A184594 A341756 * A136324 A128367 A178924 Adjacent sequences: A014451 A014452 A014453 * A014455 A014456 A014457 KEYWORD nonn AUTHOR Reinhard Zumkeller, Feb 12 2002 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 May 20 03:57 EDT 2024. Contains 372703 sequences. (Running on oeis4.)