The series: b, e, g, i, k, n, p, y, 10, 12, 14, 16, 18, 1a, 1c, 1e, 1g, 1i, 1u, 1w, 1z, 21, 23, 2b, 2e, 2g, 2i, 2k, 2m, 2o, 2r, 2t, 2v, 2x, 30, 34, 37, 39, 3c, 3e, 3g, 3i, 3m , 3o, 3q, 3s, 3v , 3y, 40, 42, 44 , 46, 48, 4a, 4d, 4g, 4n, 51, 5n, 5p, 5s, 5u, 5x, 60, 62, 64, 66, 68, 6b, 6j, 6n, 6p, 6r, 6t, 6w, 71, ...
Thanks for your help!
... 48, 4a, 4d, 4g, 4n, 51, 5n, 5p, ...
... 48, 4a, 4d, 4g, 4n, 51, 5n, 5p, ...
Also, would you care to provide some context? Is this in base 36? Are they semi-base64? What have you tried so far? What do you mean by "a formula"? What is your purpose?
In short, perhaps you could be a little clearer.
I've seen the series implemented in the facebook requests, i got really curios on how they are generated.
Broadly speaking, considering the items base 36 there's a gap of 2 or 3 between most terms with the occasional leap of 12, 14, 22, or similar. Why do you think there's a simple "formula" for these?
Just a guess, probably completely wrong in detail, but it's the sort of thing I can imagine happening. I wouldn't expect the sequence you give to have any real "formula" underneath.