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A318706 For any n >= 0 with base-9 representation Sum_{k=0..w} d_k * 9^k, let g(n) = Sum_{k=0..w} s(d_k) * 3^k (where s(0) = 0, s(1+2*j) = i^j and s(2+2*j) = i^j * (1+i) for any j > 0, and i denotes the imaginary unit); a(n) is the imaginary part of g(n). 3
0, 0, 1, 1, 1, 0, -1, -1, -1, 0, 0, 1, 1, 1, 0, -1, -1, -1, 3, 3, 4, 4, 4, 3, 2, 2, 2, 3, 3, 4, 4, 4, 3, 2, 2, 2, 3, 3, 4, 4, 4, 3, 2, 2, 2, 0, 0, 1, 1, 1, 0, -1, -1, -1, -3, -3, -2, -2, -2, -3, -4, -4, -4, -3, -3, -2, -2, -2, -3, -4, -4, -4, -3, -3, -2, -2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,19

COMMENTS

See A318705 for the real part of g and additional comments.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..6560

FORMULA

a(9 * k) = 3 * a(k) for any k >= 0.

PROG

(PARI) a(n) = my (d=Vecrev(digits(n, 9))); imag(sum(k=1, #d, if (d[k], 3^(k-1)*I^floor((d[k]-1)/2)*(1+I)^((d[k]-1)%2), 0)))

CROSSREFS

Cf. A318705.

Sequence in context: A246011 A061023 A057690 * A298199 A282623 A090589

Adjacent sequences:  A318703 A318704 A318705 * A318707 A318708 A318709

KEYWORD

sign,base

AUTHOR

Rémy Sigrist, Sep 01 2018

STATUS

approved

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Last modified January 18 23:05 EST 2019. Contains 319282 sequences. (Running on oeis4.)