#define isOdd(a) (((a) and 1) <> 0)

Function isPrime(Byval ValorEval As Integer) As Boolean
    If ValorEval < 2 Then Return False
    If ValorEval Mod 2 = 0 Then Return ValorEval = 2
    If ValorEval Mod 3 = 0 Then Return ValorEval = 3
    Dim d As Integer = 5
    While d * d <= ValorEval
        If ValorEval Mod d = 0 Then Return False Else d += 2
        If ValorEval Mod d = 0 Then Return False Else d += 4
    Wend
    Return True
End Function

Dim As Integer n
Dim As Integer p(0 To 40), pl(0 To 40)
p(0)= 0: p(1) = 1
pl(0) = 2: pl(1) = 2
For n = 2 To 40
    p(n) = 2 * p(n-1) + p(n-2)
    pl(n) = 2 * pl(n-1) + pl(n-2)
Next n

Print "First 20 Pell numbers: "
For n = 0 To 19 : Print p(n); : Next n
Print !"\n\nFirst 20 Pell-Lucas: "
For n = 0 To 19 : Print pl(n); : Next n

Print !"\n\nFirst 20 rational approximations of sqrt(2) (" & Str(Sqr(2)) & "): "
For n = 1 To 20
    Dim As Integer j = pl(n)/2, d = p(n)
    Print Using " &/& ~= &"; j; d; j/d
Next n

Print !"\nFirst 6 Pell primes: [for the limitations of the FB standard library]"
Dim as Integer pdx = 2
Dim As Byte c = 0
Dim As Ulongint ppdx(1 to 20)
do
    If isPrime(p(pdx)) Then
        If isPrime(pdx) Then ppdx(c) = pdx : End If
        Print p(pdx)
        c += 1
    End If
    pdx += 1
loop until c = 6

Print !"\nIndices of first 6 Pell primes: [for the limitations of the FB standard library]"
For n = 0 To 5 : Print " "; ppdx(n); : Next n

Dim As Ulongint nsw(0 To 20)
For n = 0 To 19
    nsw(n) = p(2*n) + p(2*n+1)
Next n
Print !"\n\nFirst 20 Newman-Shank-Williams numbers: "
For n = 0 To 19 : Print " "; nsw(n); : Next n

Print !"\n\nFirst 20 near isosceles right triangles:"
Dim As Integer i0 = 0, i1 = 1, i2, t = 1, i = 2, found = 0
Do While found < 20
    i2 = i1*2 + i0
    If isOdd(i) Then
        Print Using " [&, &, &]";  t; t+1 ; i2
        found += 1
    End If
    t += i2
    i0 = i1 : i1 = i2
    i += 1
Loop
Sleep