VOOZH about

URL: https://oeis.org/A117173

⇱ A117173 - OEIS

login
A117173
Column 3 of triangle A117170 of Inverse-Shift-Moebius coefficients and so equals the Inverse-Shift-Moebius transform of [0,0,1,0,...].
4
0, 0, 1, 0, 0, 1, 1, 1, 2, 1, 2, 2, 2, 2, 4, 2, 3, 4, 4, 3, 6, 4, 6, 6, 4, 6, 10, 6, 6, 9, 9, 8, 11, 8, 12, 12, 9, 12, 16, 11, 12, 16, 15, 15, 18, 16, 18, 19, 17, 17, 24, 19, 20, 26, 24, 25, 27, 23, 26, 28, 21, 30, 39, 29, 30, 35, 32, 33, 38, 36, 38, 41, 36, 39, 48, 42, 41, 50, 44, 48
OFFSET
1,9
PROG
(PARI) {a(n)=if(n<3, 0, prod(i=0, n, matrix(n, n, r, c, if(r>=c, if((r+i)%(c+i)==0, 1, 0))))[n, 3])}
CROSSREFS
Cf. A117170 (triangle), A117171 (column 1), A117172 (column 2), A117174 (row sums).
Sequence in context: A104659 A077197 A320510 * A384833 A241061 A103858
KEYWORD
nonn
AUTHOR
STATUS
approved