A323259 a(n) is the Y-coordinate of the n-th point of the first type of Wunderlich curve (starting at the origin and occupying the first quadrant).

0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 4, 3, 3, 4, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 8, 7, 6, 6, 7, 8, 8, 7, 6, 5, 5, 5, 4, 4, 4, 3, 3, 3, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 4, 3, 3, 4, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 10, 11, 11, 10

Offset

1,7

Links

Rémy Sigrist, Table of n, a(n) for n = 1..6561

Index entries for sequences related to coordinates of 2D curves

Prog

(PARI) s = [0, 1, 2, 2+I, 1+I, I, 2*I, 1+2*I, 2+2*I];
w = apply(z -> imag(z) + I*real(z), s);
r = [0, 1, 0, 3, 2, 3, 0, 1, 0]
a(n) = {
    my (d=if (n>1, Vecrev(digits(n-1, 9)), [0]), z=s[1+d[1]]);
    for (i=2, #d,
        my (c=(3^(i-1)-1)/2*(1+I));
        z = 3^(i-1) * w[1+d[i]] + c + (z-c) * I^r[1+d[i]];
    );
    return (imag(z));
}

Crossrefs

See A323258 for the X-coordinate and additional comments.

Sequence in context: A055224 A126295 A266686 * A330918 A162352 A285509

Adjacent sequences: A323256 A323257 A323258 * A323260 A323261 A323262

Keyword

nonn

Author

Rémy Sigrist, Jan 09 2019

Status

approved