OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..990
FORMULA
a(n) = Sum_{k=0..n} (-1)^(n-k) * (10)^k * A051731(n+1, k+1).
a(n) = (-1)^n * Sum_{d|n+1} (-10)^(d-1). - G. C. Greubel, Jun 25 2024
MATHEMATICA
A101563[n_]:= (-1)^n*DivisorSum[n+1, (-10)^(#-1) &];
Table[A101563[n], {n, 0, 40}] (* G. C. Greubel, Jun 25 2024 *)
PROG
(Magma)
A101563:= func< n | (&+[(-1)^(n-k)*(10)^k*0^((n+1) mod (k+1)): k in [0..n]]) >;
[A101563(n): n in [0..40]]; // G. C. Greubel, Jun 25 2024
(SageMath)
def A101563(n): return sum((-1)^(n+k)*(10)^k*0^((n+1)%(k+1)) for k in range(n+1))
[A101563(n) for n in range(41)] # G. C. Greubel, Jun 25 2024
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Dec 07 2004
STATUS
approved