A348916 - OEIS

A348916

a(n) is the "real" part of f(n) = Sum_{k >= 0} g(d_k) * (4 + w)^k where g(0) = 0 and g(1 + u + 2*v) = (2 + w)^u * (1 + w)^v for any u = 0..1 and v = 0..5, Sum_{k >= 0} d_k * 13^k is the base-13 representation of n and w = -1/2 + sqrt(-3)/2 is a primitive cube root of unity; sequence A348917 gives "w" parts.

0, 1, 2, 1, 1, 0, -1, -1, -2, -1, -1, 0, 1, 4, 5, 6, 5, 5, 4, 3, 3, 2, 3, 3, 4, 5, 7, 8, 9, 8, 8, 7, 6, 6, 5, 6, 6, 7, 8, 3, 4, 5, 4, 4, 3, 2, 2, 1, 2, 2, 3, 4, 2, 3, 4, 3, 3, 2, 1, 1, 0, 1, 1, 2, 3, -1, 0, 1, 0, 0, -1, -2, -2, -3, -2, -2, -1, 0, -5, -4, -3

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OFFSET

0,3

COMMENTS

For any Eisenstein integer z = u + v*w (where u and v are integers), we call u the "real" part of z and v the "w" part of z.

This sequence combines features of A334492 and of A348652.

It appears that f defines a bijection from the nonnegative integers to the Eisenstein integers.

The following diagram depicts g(d) for d = 0..12:

"w" axis

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\ 4

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