cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A318723 Let f(0) = 0 and f(t*4^k + u) = i^t * ((1+i) * 2^k - f(u)) for any t in {1, 2, 3} and k >= 0 and u such that 0 <= u < 4^k (i denoting the imaginary unit); for any n >= 0, let g(n) = (f(A042968(n)) - 1 - i) / 2; a(n) is the imaginary part of g(n).

Original entry on oeis.org

0, -1, -1, 1, 1, 0, -1, -2, -2, -2, -2, -1, 2, 2, 1, 2, 3, 3, 3, 3, 2, 1, 0, 0, -2, -3, -3, -1, -1, -2, -3, -4, -4, -4, -4, -3, -3, -3, -2, -3, -4, -4, -4, -4, -3, -2, -1, -1, 4, 4, 3, 4, 5, 5, 5, 5, 4, 3, 2, 2, 5, 6, 6, 4, 4, 5, 6, 7, 7, 7, 7, 6, 6, 6, 5, 6
Offset: 0

Views

Author

Rémy Sigrist, Sep 02 2018

Keywords

Comments

See A318722 for the real part of g and additional comments.

Crossrefs

Cf. A318722.

Programs

  • PARI
    a(n) = my (d=Vecrev(digits(1+n+n\3, 4)), z=0); for (k=1, #d, if (d[k], z = I^d[k] * (-z + (1+I) * 2^(k-1)))); imag((z-1-I)/2)

A318724 Let f(0) = 0 and f(t*4^k + u) = i^t * ((1+i) * 2^k - f(u)) for any t in {1, 2, 3} and k >= 0 and u such that 0 <= u < 4^k (i denoting the imaginary unit); for any n >= 0, let g(n) = (f(A042968(n)) - 1 - i) / 2; a(n) is the square of the modulus of g(n).

Original entry on oeis.org

1, 2, 1, 2, 5, 4, 5, 8, 5, 4, 5, 2, 8, 13, 10, 5, 10, 13, 18, 25, 20, 17, 16, 9, 13, 18, 13, 10, 17, 20, 25, 32, 25, 20, 17, 10, 10, 13, 8, 9, 16, 17, 20, 25, 18, 13, 10, 5, 32, 41, 34, 25, 34, 41, 50, 61, 52, 45, 40, 29, 29, 40, 45, 20, 17, 26, 37, 50, 53, 58
Offset: 0

Views

Author

Rémy Sigrist, Sep 02 2018

Keywords

Comments

See A318722 for the real part of g and additional comments.

Crossrefs

Programs

  • PARI
    a(n) = my (d=Vecrev(digits(1+n+n\3,4)), z=0); for (k=1, #d, if (d[k], z = I^d[k] * (-z + (1+I) * 2^(k-1)))); norm((z-1-I)/2)

Formula

a(n) = A318722(n)^2 + A318723(n)^2.
If A048647(A042968(m)) = A042968(n), then a(m) = a(n).
Showing 1-2 of 2 results.