A069078 - OEIS

%I #17 Mar 08 2022 03:39:20

%S 0,5,130,975,4100,12505,31110,67235,131080,236205,400010,644215,

%T 995340,1485185,2151310,3037515,4194320,5679445,7558290,9904415,

%U 12800020,16336425,20614550,25745395,31850520,39062525,47525530,57395655,68841500,82044625,97200030,114516635

%N a(n) = n*(4*n^4 + 1).

%D Konrad Knopp, Theory and application of infinite series, Dover, p. 268

%H Konrad Knopp, <a href="http://www.hti.umich.edu/cgi/t/text/text-idx?sid=b88432273f115fb346725f1a42422e19;c=umhistmath;idno=ACM1954.0001.001">Theorie und Anwendung der unendlichen Reihen</a>, Berlin, J. Springer, 1922. (Original German edition of "Theory and Application of Infinite Series")

%F Sum_{n>=1} (-1)^(n+1)/a(n) = log(2) - 1/2 (A187832). [Corrected by _Amiram Eldar_, Mar 08 2022]

%t a[n_] := n*(4*n^4 + 1); Array[a, 40, 0] (* _Amiram Eldar_, Mar 08 2022 *)

%Y Cf. A187832.

%K easy,nonn

%O 0,2

%A _Benoit Cloitre_, Apr 05 2002