A167754 a(1) = 1 then a(n) = (-1)*Sum_{k=1..n-1} (-1)^a(k)*floor(n/k).

1, 2, 2, 1, 3, 3, 5, 7, 8, 8, 8, 8, 8, 8, 8, 9, 11, 11, 13, 15, 17, 17, 19, 21, 24, 22, 20, 20, 20, 18, 18, 20, 18, 18, 20, 19, 21, 23, 23, 27, 29, 31, 33, 35, 35, 37, 39, 43, 46, 44, 44, 42, 42, 40, 40, 40, 40, 38, 38, 36, 36, 34, 34, 35, 37, 37, 39, 41, 43, 43, 45, 49, 51, 53, 53

Offset

1,2

Links

Table of n, a(n) for n=1..75.

Prog

(PARI)
N=100; an=vector(N);
an[1]=1; for(n=2, N, an[n]=-sum(k=1, n-1, (-1)^an[k]*floor(n/k)));
an

Crossrefs

Sequence in context: A117894 A177762 A109380 * A374434 A372688 A011020

Adjacent sequences: A167751 A167752 A167753 * A167755 A167756 A167757

Keyword

nonn

Author

Benoit Cloitre, Nov 10 2009

Status

approved