[seqfan] Distances between points in Pascal's triangle

[Charles Greathouse]

Consider three consecutive binomial coefficients in Pascal's triangle x =
binomial(n, k), y = binomial(n,k+1), and z = binomial(n, k+2) such that the
distance sqrt((x-y)^2 + (y-z)^2) between (x, y) and (y, z) is an integer.

J. M. Bergot poses this question: why is n so often odd rather than even?

Charles Greathouse
Analyst/Programmer
Case Western Reserve University