OFFSET
1,2
COMMENTS
Residues mod 10 are 9,3,1,9,1,9,1,9,1,9,1,9,1,9,1,9,1,9,1,9,...
MATHEMATICA
t[n_] := Sum[(-1)^(k - 1) k*(n - k + 1)!, {k, 1, n + 1}]
Table[t[n], {n, 1, 30}]
CROSSREFS
KEYWORD
sign
AUTHOR
Clark Kimberling, Jul 25 2024
STATUS
approved