A176337 a(n) = 1 + (1-2^n)*a(n-1) for n > 0, a(0)=0.

0, 1, -2, 15, -224, 6945, -437534, 55566819, -14169538844, 7240634349285, -7407168939318554, 15162474818785080039, -62090334382924902759704, 508581928930537878504735465, -8332097741669002063543081123094

Offset: 0

Author

Roger L. Bagula, Apr 15 2010

Keywords

• sign
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..80

Crossrefs

Cf. A176338.

Programs

GAP

a:= function(n,q)
    if n=0 then return 0;
    else return 1 - (q^n-1)*a(n-1,q);
    fi; end;
List([0..15], n-> a(n,2) ); # G. C. Greubel, Dec 07 2019

Magma

function a(n,q)
  if n eq 0 then return 0;
  else return 1 - (q^n-1)*a(n-1,q);
  end if; return a; end function;
[a(n,2): n in [0..15]]; // G. C. Greubel, Dec 07 2019

Maple

A176337 := proc(n)
    if n = 0 then
        0;
    else
        1+(1-2^n)*procname(n-1) ;
    end if;
end proc: # R. J. Mathar, May 04 2013

Mathematica

a[n_, q_]:= a[n, q]= If[n==0, 0, (1-q^n)*a[n-1, q] +1]; Table[a[n, 2], {n,0,15}]

PARI

q=2; a(n,q) = if(n==0, 0, 1 -(q^n-1)*a(n-1,q) );
vector(15, n, a(n-1, 2)) \\ G. C. Greubel, Dec 07 2019

Sage

def a(n, q):
    if (n==0): return 0
    else: return 1 - (q^n-1)*a(n-1,q)
[a(n,2) for n in (0..15)] # G. C. Greubel, Dec 07 2019