Maths & numbers

Strict ballot sequence count calculator

Count vote orders in which candidate A is ahead at every nonempty prefix.

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Behind the numbers

How this calculation works

Count vote orders in which candidate A is ahead at every nonempty prefix.

THE FORMULACount = C(a+b,a) × (a−b)/(a+b) for a>b

A worked example

Five votes versus three give 56 possible orders, of which 14 keep A strictly ahead.

Good to know

A tied prefix is excluded. Votes within each candidate group are indistinguishable.

Read the result

Count vote orders in which candidate A is ahead at every nonempty prefix.

The primary result is labeled “Valid counting orders”. Keep the input definitions in view when comparing this result with another method.

Try a related calculation

A tied prefix is excluded. Votes within each candidate group are indistinguishable.

For a related exercise, try the greatest common divisor.

A few questions, answered

How can I check the default inputs by hand?

Five votes versus three give 56 possible orders, of which 14 keep A strictly ahead.

Which rule does this calculator apply?

Count = C(a+b,a) × (a−b)/(a+b) for a>b

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