This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a(1) = 0 because 1 is the only positive integer <= 1. a(2) = 0 because 1 and 2 are the only two positive integers <= 2, and sqrt(1*2) is not an integer. a(4) = 1 because 2 = sqrt(1*4). a(8) = 2 because 2 = sqrt(1*4) and 4 = sqrt(2*8). a(9) = 4 because 2 = sqrt(1*4), 3 = sqrt(1*9), 4 = sqrt(2*8), and 6 = sqrt(4*9). a(16) = 6 because 2 = sqrt(1*4), 3 = sqrt(1*9), 4 = sqrt(2*8), 6 = sqrt(4*9), 8 = sqrt(4*16), and 12 = sqrt(9*16).
a(n)={sum(i=1, n, sum(j=1, i-1, i^2%j==0 && i^2/j<=n)>0)} \\ Andrew Howroyd, May 15 2020
list1 = []
list2 = []
nmax = 100
for i in range(1, nmax+1):
list1.append(i*i)
for j in range(1, i+1):
for k in range(j+1, i+1):
m = j*k
if m in list1:
list1.remove(m)
list2.append(m)
print(i, len(list2))
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