A061787 - OEIS

%I #23 Jul 16 2022 12:54:43

%S 1,28,3153,826696,388247185,285699917796,303160806510049,

%T 438197051187369424,827678458937524133601,1979247334119251113257580,

%U 5844566265720101772494382001,20886312566113632136127527292568

%N a(n) = Sum_{k=1..n} (2k-1)^(2k-1).

%H Harry J. Smith, <a href="/A061787/b061787.txt">Table of n, a(n) for n = 1..100</a>

%F a(n) ~ exp(-1) * 2^(2*n-1) * n^(2*n-1). - _Vaclav Kotesovec_, Dec 09 2021

%e a(3) = 1 + 3^3 + 5^5 = 3153.

%t Array[Sum[(2 k - 1)^(2 k - 1), {k, #}] &, 12] (* _Michael De Vlieger_, Jul 01 2018 *)

%t Accumulate[#^#&/@Range[1,25,2]] (* _Harvey P. Dale_, Jul 16 2022 *)

%o (PARI) { a=n=0; forstep (p=1, 200, 2, write("b061787.txt", n++, " ", a+=p^p) ) } \\ _Harry J. Smith_, Jul 28 2009

%o (GAP) List([1..13],n->Sum([1..n],k->(2*k-1)^(2*k-1))); # _Muniru A Asiru_, Jul 01 2018

%Y Partial sums of A085529.

%K nonn,easy

%O 1,2

%A _Amarnath Murthy_, May 25 2001

%E Corrected and extended by _Jason Earls_, May 27 2001