(PARI)a(n)=总和(k=1,n,n\k*3^(k-1));
(PARI)a(n)=总和(k=1,n,sumdiv(k,d,3^(d-1)));
(PARI)我的(N=40,x='x+O('x^N));Vec(和(k=1,N,x^k/(1-3*x^k))/(1-x))
(PARI)我的(N=40,x='x+O('x^N));Vec(总和(k=1,N,3^(k-1)*x^k/(1-x^k))/(1-x))
(岩浆)
A344814飞机:=函数<n|(&+[楼层(n/k)*3^(k-1):[1..n]]中的k)>;
(SageMath)
定义A344814飞机(n) :返回范围(1,n+1)中k的总和((n//k)*3^(k-1))