A094496 Triangle read by rows: T(n,k) = binomial(n,k) - binomial(n,k) mod n^2, with T(0,0) = 1.
1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 64, 0, 0, 0, 0, 0, 0, 0, 81, 81, 81, 81, 0, 0, 0, 0, 0, 0, 100, 200, 200, 200, 100, 0, 0, 0, 0, 0, 0, 121, 242, 363, 363, 242, 121, 0, 0, 0, 0, 0, 0, 144, 432, 720, 864, 720, 432, 144, 0, 0, 0
Offset: 0
Examples
Triangle begins: 1; 1, 1; 0, 0, 0; 0, 0, 0, 0; 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 64, 0, 0, 0, 0; 0, 0, 0, 81, 81, 81, 81, 0, 0, 0; 0, 0, 0, 100, 200, 200, 200, 100, 0, 0, 0; ... T(8,6) = binomial(8,4) - binomial(8,4) mod 8^2 = 70 - 6 = 64.
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..1325 (rows 0..50)
Programs
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Mathematica
Flatten[Table[Table[Binomial[n, j]-Mod[Binomial[n, j], n^2], {j, 0, n}], {n, 1, 20}], 1]
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PARI
T(n,k) = my(x=binomial(n,k)); x - if(n, x % n^2) \\ Andrew Howroyd, Dec 12 2024