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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A359085 Odd numbers k such that A246601(k) > 2*k.

Original entry on oeis.org

4095, 16777215, 33550335, 67096575, 134189055, 268374015, 536743935, 1073483775, 2146963455, 4293922815, 8587841535, 17175678975, 34351353855, 68702703615, 68719476735, 137405403135, 137422176255, 137438949375, 274810802175, 274827575295, 274844348415, 274877894655
Offset: 1

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Author

Amiram Eldar, Dec 15 2022

Keywords

Comments

These are the odd terms of A359084 and also its primitive terms, since if m is a term then m*2^k is a term of A359084 for all k >= 0.
The least term that is not divisible by 4095 is a(29) = 1099511627775 = 2^40 - 1.

Links

Crossrefs

Cf. A246601.
Subsequence of A005101, A005231 and A359084.

Programs

  • Mathematica
    s[n_] := DivisorSum[n, # &, BitAnd[n, #] == # &]; Select[Range[1, 2^24, 2], s[#] > 2*# &]
  • PARI
    is(n) = n%2 && sumdiv(n, d, d * (bitor(n, d) == n)) > 2*n;
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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