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) {an=vector(1000); }{a(n)=if(n<0, 0, an[n]); }{an[1]=1; }{for(n=2, 1000, an[n]=-sum(k=1, n-1, (-1)^a(k)*floor(n/k))}

Crossrefs

Sequence in context: A117894 A177762 A109380 * A011020 A181512 A076019

Adjacent sequences: A167751 A167752 A167753 * A167755 A167756 A167757

Keyword

nonn

Author

Benoit Cloitre, Nov 10 2009

Status

approved