OFFSET
1,3
FORMULA
G.f.: (1-4*x^2+6*x^4-x^5-4*x^6+3*x^7+x^8-3*x^9+x^10+2*x^11-x^12) / ((1-x)*(1-2*x^2)*(1+x^4)*(1-4*x^2+6*x^4-4*x^6+2*x^8)).
PROG
(PARI) {m=44; M=matrix(m, m); for(j=1, m, M[j, 1]=if((j-1)%8<4, 1, 0)); for(k=2, m, for(j=k, m, M[j, k]=M[j-1, k-1]+M[j, k-1])); for(j=1, m, print1(sum(k=1, (j+1)\2, M[j-k+1, k]), ", "))}
(Magma) m:=44; M:=ZeroMatrix(IntegerRing(), m, m); for j:=1 to m do if (j-1) mod 8 lt 4 then M[j, 1]:=1; end if; end for; for k:=2 to m do for j:=k to m do M[j, k]:=M[j-1, k-1]+M[j, k-1]; end for; end for; [ &+[ M[j-k+1, k]: k in [1..(j+1) div 2] ]: j in [1..m] ];
CROSSREFS
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 14 2007
STATUS
approved