In particular, he summed 1 − 2 + 3 − 4 + ..., to ​1⁄4 by a method that may be rephrased as (C, n) but was not justified as such at the time.
În special, el a obținut suma de 1⁄4 pentru 1 − 2 + 3 − 4 + ..., printr-o metodă care poate fi acum numită (C, n), dar care nu era justificată la momentul respectiv.