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

1,2

Links

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

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A253249(n/d) * a(d).

Prog

(PARI)
A074206(n) = if(n>1, sumdiv(n, i, if(i<n, A074206(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(d<n, A253249(n/d)*A378219(d), 0)); mapput(memoA378219, n, v); (v)));

Crossrefs

Cf. A074206, A253249.

Sequence in context: A262212 A378451 A123676 * A326814 A374902 A122775

Adjacent sequences: A378216 A378217 A378218 * A378220 A378221 A378222

Keyword

sign

Author

Antti Karttunen, Nov 23 2024

Status

approved