A378219 Dirichlet inverse of A253249.

1, -3, -3, 2, -3, 7, -3, 0, 2, 7, -3, -4, -3, 7, 7, 0, -3, -4, -3, -4, 7, 7, -3, 0, 2, 7, 0, -4, -3, -15, -3, 0, 7, 7, 7, 2, -3, 7, 7, 0, -3, -15, -3, -4, -4, 7, -3, 0, 2, -4, 7, -4, -3, 0, 7, 0, 7, 7, -3, 8, -3, 7, -4, 0, 7, -15, -3, -4, 7, -15, -3, 0, -3, 7, -4, -4, 7, -15, -3, 0, 0, 7, -3, 8, 7, 7, 7, 0, -3, 8, 7

Offset: 1

Author

Antti Karttunen, Nov 23 2024

Keywords

• sign

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A074206, A253249.

Programs

PARI

A074206(n) = if(n>1, sumdiv(n, i, if(iA074206(i))), n); \\ From A074206
A253249(n) = if(1==n,n,4*A074206(n)-1);
memoA378219 = Map();
A378219(n) = if(1==n,1,my(v); if(mapisdefined(memoA378219,n,&v), v, v = -sumdiv(n,d,if(dA253249(n/d)*A378219(d),0)); mapput(memoA378219,n,v); (v)));

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA253249(n/d) * a(d).