OFFSET
0,3
COMMENTS
See A099884 for the definitions of the XOR BINOMIAL transform and the XOR difference triangle.
FORMULA
a(2^n) = 3*2^(n-1) for n>0, with a(0)=0, a(1) = 1 and a(k)=0 otherwise. a(n) = SumXOR_{i=0..n} (C(n, i)mod 2)*A003188(n-i), where A003188(k)=bitxor(k, [k/2]) and SumXOR is summation under XOR.
Multiplicative with a(2^e) = 3*2^(e-1), a(p^e) = 0 otherwise. - David W. Wilson, Jun 12 2005
Dirichlet g.f.: (2^s+1)/(2^s-2). - R. J. Mathar, Apr 14 2011
MATHEMATICA
a[n_] := Module[{e = IntegerExponent[n, 2]}, If[n == 2^e, 3*2^(e-1), 0]]; Array[a, 100, 0] (* Amiram Eldar, Aug 31 2023 *)
PROG
(PARI) {a(n)=local(B); B=0; for(i=0, n, B=bitxor(B, binomial(n, i)%2*(bitxor((n-i), (n-i)\2)))); B}
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Paul D. Hanna, Oct 29 2004
STATUS
approved