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.

A283973 Numbers n such that A007306(n) = A283986(n); positions of zeros in A283988.

Original entry on oeis.org

1, 3, 4, 9, 10, 12, 13, 15, 16, 21, 22, 27, 28, 33, 36, 37, 48, 49, 60, 61, 64, 78, 84, 85, 87, 88, 90, 91, 93, 94, 99, 100, 102, 103, 105, 106, 108, 109, 115, 129, 130, 133, 135, 136, 141, 144, 145, 153, 159, 160, 162, 171, 172, 189, 190, 192, 193, 195, 196, 213, 214, 223, 225, 226, 232, 240, 241, 244, 249, 250, 252, 255, 256
Offset: 1

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Author

Antti Karttunen, Mar 21 2017

Keywords

Comments

Equally, numbers n for which A007306(n) = A283987(n), or equally, numbers n for which A283986(n) = A283987(n).
Numbers n such that the binary representations of A002487(n-1) and A002487(n) have no 1-bits in common shared positions.

Crossrefs

Cf. A283974 (complement).

Programs

  • Mathematica
    a[0] = 0; a[1] = 1; a[n_] := If[EvenQ@ n, a[n/2], a[(n - 1)/2] + a[(n + 1)/2]]; Map[Function[n, If[EvenQ@ n, a[n/2], BitOr[a[#], a[# + 1]] &[(n - 1)/2]]], 2 Range[99] - 1] (* Michael De Vlieger, Mar 22 2017 *)
  • PARI
    A(n) = if(n<2, n, if(n%2, A(n\2) + A((n + 1)/2), A(n/2)));
    D(n) = if(n<1, 1, sum(k=0, n, binomial(n + k - 1, 2*k)%2)) /* A007306 */
    for(n=1, 300, if(bitor(A(n - 1), A(n)) == D(n), print1(n,", "))) \\ Indranil Ghosh, Mar 23 2017