0,4

T(n,k) = [A132844^n](n,k) where A132844(n,k) = T( [(n+k)/2], k) for n>=k>=0.

Triangle T begins:

1;

1, 1;

3, 2, 1;

13, 9, 3, 1;

73, 42, 18, 4, 1;

466, 270, 95, 30, 5, 1;

3309, 1785, 693, 179, 45, 6, 1;

25425, 13657, 4893, 1463, 301, 63, 7, 1;

209717, 108606, 40506, 11104, 2726, 468, 84, 8, 1;

1837168, 943677, 338277, 99177, 22239, 4653, 687, 108, 9, 1;

16995545, 8534290, 3110310, 873440, 213415, 40707, 7440, 965, 135, 10, 1; ...

Triangle A132844 begins:

1;

1, 1;

1, 1, 1;

1, 2, 1, 1;

3, 2, 3, 1, 1;

3, 9, 3, 4, 1, 1;

13, 9, 18, 4, 5, 1, 1; ...

where column k of A132844 equals column k of T with terms repeated;

then row n of T equals row n of A132844^n as illustrated below.

Matrix square A132844^2 begins:

1;

2, 1;

3, 2, 1; <-- row 2 of T

5, 5, 2, 1;

12, 9, 7, 2, 1;

25, 31, 13, 9, 2, 1; ...

Matrix cube A132844^3 begins:

1;

3, 1;

6, 3, 1;

13, 9, 3, 1; <-- row 3 of T

33, 22, 12, 3, 1;

87, 75, 31, 15, 3, 1; ...

Matrix 4-th power A132844^4 begins:

1;

4, 1;

10, 4, 1;

26, 14, 4, 1;

73, 42, 18, 4, 1; <-- row 4 of T

220, 151, 58, 22, 4, 1; ...

(PARI) {T(n, k)=local(M=matrix(n+1, n+1, r, c, if(r>=c, if(r<=c+1, 1, T((r+c)\2-1, c-1))))); (M^n)[n+1, k+1]}

Cf. A132844 (triangle); columns: A132846, A132847, A132848, A132849.

Sequence in context: A156628 A104980 A134090 this_sequence A129652 A154921 A127126

Adjacent sequences: A132842 A132843 A132844 this_sequence A132846 A132847 A132848

nonn,tabl

Paul D. Hanna (pauldhanna(AT)juno.com), Sep 17 2007