A374652 - OEIS

%I #12 Aug 27 2024 16:50:00

%S -1,5,5,39,181,1159,8301,67919,621941,6308679,70223101,851165119,

%T 11160489861,157411458359,2376543620621,38242755444399,

%U 653435591570581,11815320900966439,225408497129888541,4524816801601368479,95339744251262894501,2103888092422797642519

%N a(n) = Sum_{k=1..n+1} (-1)^(k - 1)*(k + 1)*(n - k + 1)!.

%C Residues mod 10 are 9, 5, 5, 9, 1, 9, 1, 9, 1, 9, 1, 9, 1, 9, 1, 9, 1, 9,...

%t t[n_] := Sum[(-1)^(k - 1) (k + 1)*(n - k + 1)!, {k, 1, n + 1}]

%t Table[t[n], {n, 1, 30}]

%Y Cf. A374651, A374653.

%K sign

%O 1,2

%A _Clark Kimberling_, Jul 25 2024

%E Definition corrected by _Georg Fischer_, Aug 27 2024