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URL: https://oeis.org/A176338

⇱ A176338 - OEIS

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A176338
a(n) = 1 + (1-3^n)*a(n-1) for n >=1, a(0) = 0.
4
0, 1, -7, 183, -14639, 3542639, -2579041191, 5637784043527, -36983863325537119, 727916397973221576159, -42982007467522787629036631, 7614090694841791737333323035127, -4046432358866721800888421193787892879
OFFSET
0,3
LINKS
MAPLE
A176338 := proc(n)
if n = 0 then
0;
else
1+(1-3^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, 3], {n, 0, 15}]
nxt[{n_, a_}]:={n+1, a(1-3^(n+1))+1}; NestList[nxt, {0, 0}, 20][[;; , 2]] (* Harvey P. Dale, Dec 31 2024 *)
PROG
(PARI) q=3; a(n, q) = if(n==0, 0, 1 -(q^n-1)*a(n-1, q) );
vector(16, n, a(n-1, 3)) \\ 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, 3): n in [0..15]]; // G. C. Greubel, Dec 07 2019
(SageMath)
def a(n, q):
if (n==0): return 0
else: return 1 - (q^n-1)*a(n-1, q)
[a(n, 3) for n in (0..15)] # G. C. Greubel, Dec 07 2019
(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, 3) ); # G. C. Greubel, Dec 07 2019
CROSSREFS
Cf. A176337.
Sequence in context: A217243 A217244 A152436 * A012843 A012798 A297765
KEYWORD
sign,easy
AUTHOR
Roger L. Bagula, Apr 15 2010
STATUS
approved