Motzkin numbers: Difference between revisions
Content added Content deleted
m (→{{header|C#|CSharp}}: extended to 80th, added comment) |
m (→{{header|C#|CSharp}}: added missing ordinal number suffix in comment) |
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if (x < 4) return x == 1; |
if (x < 4) return x == 1; |
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if ((x & 1) == 0 || x % 3 == 0) return true; |
if ((x & 1) == 0 || x % 3 == 0) return true; |
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int l = (int)Math.Sqrt((double)x); // this limit works because the 40th to |
int l = (int)Math.Sqrt((double)x); // this limit works because the 40th to 80th Motzkin numbers have factors of 2 or 3 |
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for (int j = 5, d = 4; j <= l; j += d = 6 - d) |
for (int j = 5, d = 4; j <= l; j += d = 6 - d) |
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if (x % j == 0) return x > j; |
if (x % j == 0) return x > j; |
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