OFFSET
0,8
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1274
FORMULA
T(n,f) = T(n,n-f), flipping all node colors.
EXAMPLE
The triangle starts
1;
1, 1;
1, 1, 1;
1, 2, 2, 1;
2, 4, 6, 4, 2;
3, 9, 15, 15, 9, 3;
6, 20, 43, 51, 43, 20, 6;
11, 48, 116, 175, 175, 116, 48, 11;
23, 115, 329, 573, 698, 573, 329, 115, 23;
47, 286, 918, 1866, 2626, 2626, 1866, 918, 286, 47;
106, 719,2609, 5978, 9656,11241, 9656,5978,2609,719,106;
235,1842,
PROG
(PARI)
R(n, y)={my(v=vector(n)); v[1]=1; for(k=1, n-1, my(p=(1+y)*v[k]); my(q=Vec(prod(j=0, poldegree(p, y), (1/(1-x*y^j) + O(x*x^(n\k)))^polcoeff(p, j)))); v=vector(n, j, v[j] + sum(i=1, (j-1)\k, v[j-i*k] * q[i+1]))); v; }
M(n)={my(B=(1+y)*x*Ser(R(n, y))); 1 + B - (B^2 - substvec(B, [x, y], [x^2, y^2]))/2}
{ my(A=M(10)); for(n=0, #A-1, print(Vecrev(polcoeff(A, n)))) } \\ Andrew Howroyd, May 12 2018
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
R. J. Mathar, Apr 16 2018
EXTENSIONS
Row 10 completed. - R. J. Mathar, Apr 29 2018
STATUS
approved