This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A319194 a(n) = Sum_{k=1..n} sigma(n,k). 5
 1, 6, 38, 373, 4461, 68033, 1202753, 24757484, 574608039, 14925278329, 427729375161, 13424413453317, 457608305315211, 16841852554413561, 665483754539870667, 28101844918556128030, 1262901795439193700478, 60182608193322255156347, 3031285556584399354961535 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Vaclav Kotesovec, Table of n, a(n) for n = 1..380 FORMULA a(n) ~ n^n / (1 - exp(-1)). a(n) = Sum_{k=1..n} k^n * floor(n/k). - Daniel Suteu, Nov 10 2018 MATHEMATICA Table[Sum[DivisorSigma[n, k], {k, 1, n}], {n, 1, 20}] PROG (PARI) a(n) = sum(k=1, n, sigma(k, n)); \\ Michel Marcus, Sep 13 2018 (PARI) a(n) = sum(k=1, n, k^n * (n\k)); \\ Daniel Suteu, Nov 10 2018 CROSSREFS Cf. A065805. Sequence in context: A075197 A276473 A062814 * A303865 A319647 A239983 Adjacent sequences:  A319191 A319192 A319193 * A319195 A319196 A319197 KEYWORD nonn AUTHOR Vaclav Kotesovec, Sep 13 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.

Last modified August 18 08:57 EDT 2019. Contains 326077 sequences. (Running on oeis4.)