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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A091945 Numbers n such that there is no k, 0 <= k < n, satisfying A002487(k) = A002487(n).

Original entry on oeis.org

0, 1, 3, 5, 9, 11, 19, 21, 33, 35, 37, 39, 43, 45, 69, 73, 75, 77, 83, 85, 93, 139, 141, 147, 149, 151, 153, 155, 165, 171, 173, 189, 267, 275, 277, 279, 283, 293, 297, 299, 301, 309, 315, 325, 331, 333, 339, 341, 365, 537, 549, 553, 555, 563, 565, 567, 579, 585
Offset: 1

Views

Author

Benoit Cloitre, Mar 11 2004

Keywords

Links

Crossrefs

Cf. A002487, A091926.

Programs

Extensions

Leading 0 inserted and name adapted by Rémy Sigrist, Dec 07 2022

A295079 a(n) = least k > n such that A002487(k) = A002487(n).

Original entry on oeis.org

2, 4, 6, 8, 7, 12, 10, 16, 15, 14, 13, 24, 17, 20, 18, 32, 22, 30, 23, 28, 27, 26, 25, 48, 29, 31, 42, 40, 38, 36, 34, 64, 63, 44, 47, 60, 41, 46, 57, 56, 55, 54, 53, 52, 51, 50, 49, 96, 61, 58, 90, 62, 71, 84, 59, 80, 78, 65, 67, 72, 70, 68, 66, 128, 76, 126
Offset: 1

Views

Author

Rémy Sigrist, Nov 13 2017

Keywords

Comments

See A091926 for the least k such that A002487(k) = A002487(n).
For any n > 0, a(n) <= 2*n, with equality iff n belongs to A029744.
For any n > 0, there is a constant i >= 0 such that for any k >= 0, a^(i + k*A000010(A002487(n)))(n) = 2^k * a^i(n) (where a^m denotes the m-th iterate of the sequence a); this comes from the fact that a value v > 0 eventually appears A000010(v) times in each row of A002487.

Examples

			A002487(n) = 5 for n = 11, 13, 17, 22, 26, 31, 34, 44, 52, 62, ...
Hence a(11) = 13, a(13) = 17, a(17) = 22, a(22) = 26, etc.

Links

Crossrefs

Cf. A000010, A002487, A029744, A091926.

Programs

  • PARI
    fusc(n)=local(a=1, b=0); while(n>0, if(bitand(n, 1), b+=a, a+=b);n>>=1); b \\ after Charles R Greathouse IV at A002487
a(n) = my (v=fusc(n)); for (k=n+1, oo, if (fusc(k)==v, return (k)))
Showing 1-2 of 2 results.

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