Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #11 Feb 01 2019 03:06:28
%S 1,2,8,16,80,160,640,1280,6560,13120,52480,104960,524800,1049600,
%T 4198400,8396800,43046720,86093440,344373760,688747520,3443737600,
%U 6887475200,27549900800,55099801600,282386483200,564772966400
%N Inverse modulo 2 binomial transform of 3^n.
%C 3^n may be retrieved as Sum_{k=0..n} (binomial(n,k) mod 2)*A100736(k).
%F a(n) = Sum_{k=0..n} (-1)^A010060(n-k)*(binomial(n, k) mod 2)*3^k.
%o (PARI) a(n)=abs(sum(k=0, n, (-1)^(hammingweight(k)%2)* lift(Mod(binomial(n, k), 2))*3^k)) \\ _Jianing Song_, Jan 27 2019
%Y Cf. A010060, A100735.
%K easy,nonn
%O 0,2
%A _Paul Barry_, Dec 06 2004