OFFSET
1,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..345
FORMULA
a(n) = (1/4) * (n+1) * (-2*(n+2))^n. - Andrei Asinowski, Nov 03 2015
MATHEMATICA
(* First program *)
f[j_]:= 1/(2 j + 2); z = 12;
v[n_]:= Product[Product[f[k] - f[j], {j, k-1}], {k, 2, n}];
1/Table[v[n], {n, z}] (* A203426 *)
Table[v[n]/(4 v[n + 1]), {n, z}] (* A203427 *)
(* Second program *)
Table[(-2*(n+2))^n*(n+1)/4, {n, 20}] (* G. C. Greubel, Dec 05 2023 *)
PROG
(Magma) [(-2*(n+2))^n*(n+1)/4: n in [1..20]]; // G. C. Greubel, Dec 05 2023
(SageMath) [(-2*(n+2))^n*(n+1)/4 for n in range(1, 21)] # G. C. Greubel, Dec 05 2023
CROSSREFS
KEYWORD
sign
AUTHOR
Clark Kimberling, Jan 02 2012
EXTENSIONS
Name corrected by Andrei Asinowski, Nov 03 2015
Terms a(14) onward added by G. C. Greubel, Dec 05 2023
STATUS
approved