OFFSET
1,18
COMMENTS
The reversed rows (see example) stabilize to A027193. [Joerg Arndt, May 12 2013]
FORMULA
G.f. (including term a(0)=1): sum(n>=0, q^(2*n)/prod(k=1..2*n, 1-z*q^k) ), set z=1 to obtain g.f. for A027187. [Joerg Arndt, May 12 2013]
EXAMPLE
G.f. = (1)*q^0 +
(0) * q^1 +
(1 + 0*z) * q^2 +
(0 + 1*z + 0*z^2) * q^3 +
(1 + 1*z + 1*z^2 + 0*z^3) * q^4 +
(0 + 1*z + 1*z^2 + 1*z^3 + 0*z^4) * q^5 +
(1 + 1*z + 2*z^2 + 1*z^3 + 1*z^4 + 0*z^5) * q^6 +
(0 + 2*z + 1*z^2 + 2*z^3 + 1*z^4 + 1*z^5 + 0*z^6) * q^7 +
... [Joerg Arndt, May 12 2013]
Triangle starts:
01: [0]
02: [1, 0]
03: [0, 1, 0]
04: [1, 1, 1, 0]
05: [0, 1, 1, 1, 0]
06: [1, 1, 2, 1, 1, 0]
07: [0, 2, 1, 2, 1, 1, 0]
08: [1, 2, 3, 2, 2, 1, 1, 0]
09: [0, 2, 3, 3, 2, 2, 1, 1, 0]
10: [1, 2, 5, 4, 4, 2, 2, 1, 1, 0]
11: [0, 3, 4, 6, 4, 4, 2, 2, 1, 1, 0]
12: [1, 3, 7, 7, 7, 5, 4, 2, 2, 1, 1, 0]
13: [0, 3, 6, 10, 8, 7, 5, 4, 2, 2, 1, 1, 0]
14: [1, 3, 9, 11, 13, 9, 8, 5, 4, 2, 2, 1, 1, 0]
15: [0, 4, 8, 14, 14, 14, 9, 8, 5, 4, 2, 2, 1, 1, 0]
16: [1, 4, 12, 16, 20, 17, 15, 10, 8, 5, 4, 2, 2, 1, 1, 0]
17: [0, 4, 11, 20, 22, 23, 18, 15, 10, 8, 5, 4, 2, 2, 1, 1, 0]
18: [1, 4, 15, 23, 30, 28, 26, 19, 16, 10, 8, 5, 4, 2, 2, 1, 1, 0]
19: [0, 5, 13, 28, 33, 37, 31, 27, 19, 16, 10, 8, 5, 4, 2, 2, 1, 1, 0]
20: [1, 5, 18, 31, 44, 44, 43, 34, 28, 20, 16, 10, 8, 5, 4, 2, 2, 1, 1, 0]
... [Joerg Arndt, May 12 2013]
PROG
(PARI)
N = 20; q = 'q + O('q^N);
gf = sum(n=0, N, q^(2*n)/prod(k=1, 2*n, 1-'z*q^k) );
v = Vec(gf);
{ for(n=2, #v, /* print triangle starting with row 1: */
p = Pol('c0 +'cn*'z^n + v[n], 'z);
p = polrecip(p);
p = Vec(p);
p[1] -= 'c0;
p = vector(#p-2, j, p[j]);
print(p);
); }
/* Joerg Arndt, May 12 2013 */
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
STATUS
approved