OFFSET
0,5
COMMENTS
T(n,k) is defined for all n >= 0 and k >= 0. Terms that are not in the triangle are zero.
LINKS
Alois P. Heinz, Rows n = 0..2^12-1, flattened
Wikipedia, Iverson bracket
FORMULA
T(n,k) = T(n-1,k) + [A000120(n) = k] where [] is the Iverson bracket and T(n,k) = 0 for n<0.
T(2^n-1,k) = A007318(n,k) = binomial(n,k).
T(n,floor(log_2(n+1))) = A090996(n+1).
Sum_{k>=0} T(n,k) = n+1.
Sum_{k>=0} k * T(n,k) = A000788(n).
Sum_{k>=0} k^2 * T(n,k) = A231500(n).
Sum_{k>=0} k^3 * T(n,k) = A231501(n).
Sum_{k>=0} k^4 * T(n,k) = A231502(n).
Sum_{k>=0} 2^k * T(n,k) = A006046(n+1).
Sum_{k>=0} 3^k * T(n,k) = A130665(n).
Sum_{k>=0} 4^k * T(n,k) = A116520(n+1).
Sum_{k>=0} 5^k * T(n,k) = A130667(n+1).
Sum_{k>=0} 6^k * T(n,k) = A116522(n+1).
Sum_{k>=0} 7^k * T(n,k) = A161342(n+1).
Sum_{k>=0} 8^k * T(n,k) = A116526(n+1).
Sum_{k>=0} 10^k * T(n,k) = A116525(n+1).
Sum_{k>=0} n^k * T(n,k) = A361257(n).
EXAMPLE
T(6,2) = 3: 3, 5, 6, or in binary: 11_2, 101_2, 110_2.
T(15,3) = 4: 7, 11, 13, 14, or in binary: 111_2, 1011_2, 1101_2, 1110_2.
Triangle T(n,k) begins:
1;
1, 1;
1, 2;
1, 2, 1;
1, 3, 1;
1, 3, 2;
1, 3, 3;
1, 3, 3, 1;
1, 4, 3, 1;
1, 4, 4, 1;
1, 4, 5, 1;
1, 4, 5, 2;
1, 4, 6, 2;
1, 4, 6, 3;
1, 4, 6, 4;
1, 4, 6, 4, 1;
...
MAPLE
b:= proc(n) option remember; `if`(n<0, 0,
b(n-1)+x^add(i, i=Bits[Split](n)))
end:
T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n)):
seq(T(n), n=0..23);
CROSSREFS
KEYWORD
AUTHOR
Alois P. Heinz, Mar 04 2023
STATUS
approved