The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A124403 a(n) = -1 + Sum_{i=1..n} Sum_{j=1..n} i^j. 1
 0, 7, 55, 493, 5698, 82199, 1419759, 28501115, 651233660, 16676686695, 472883843991, 14705395791305, 497538872883726, 18193397941038735, 714950006521386975, 30046260016074301943, 1344648068888240941016 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS p divides a(p-2) for prime p>2. p^k divides a(p^k-2) for prime p>2. LINKS G. C. Greubel, Table of n, a(n) for n = 1..385 FORMULA a(n) = -1 + Sum_{i=1..n} Sum_{j=1..n} i^j. a(n) = n - 1 + Sum_{j=2..n} j*(j^n - 1)/(j-1). a(n) = A086787(n) - 1. MAPLE seq( n-1+add(j*(j^n-1)/(j-1), j=2..n), n=1..30); # G. C. Greubel, Dec 25 2019 MATHEMATICA Table[Sum[i^j, {i, 1, n}, {j, 1, n}]-1, {n, 1, 25}] PROG (PARI) vector(30, n, n-1 + sum(j=2, n, j*(j^n-1)/(j-1)) ) \\ G. C. Greubel, Dec 25 2019 (MAGMA) [0] cat [n-1 + (&+[j*(j^n-1)/(j-1): j in [2..n]]): n in [2..30]]; // G. C. Greubel, Dec 25 2019 (Sage) [n-1 + sum(j*(j^n-1)/(j-1) for j in (2..n)) for n in (1..30)] # G. C. Greubel, Dec 25 2019 (GAP) List([1..30], n-> n-1 + Sum([2..n], j-> j*(j^n-1)/(j-1)) ); # G. C. Greubel, Dec 25 2019 CROSSREFS Cf. A086787. Sequence in context: A096307 A199564 A225032 * A005012 A123784 A091695 Adjacent sequences:  A124400 A124401 A124402 * A124404 A124405 A124406 KEYWORD nonn AUTHOR Alexander Adamchuk, Dec 14 2006 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 10 08:44 EDT 2020. Contains 336369 sequences. (Running on oeis4.)