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.

Showing 1-3 of 3 results.

A236840 n minus number of runs in the binary expansion of n: a(n) = n - A005811(n).

Original entry on oeis.org

0, 0, 0, 2, 2, 2, 4, 6, 6, 6, 6, 8, 10, 10, 12, 14, 14, 14, 14, 16, 16, 16, 18, 20, 22, 22, 22, 24, 26, 26, 28, 30, 30, 30, 30, 32, 32, 32, 34, 36, 36, 36, 36, 38, 40, 40, 42, 44, 46, 46, 46, 48, 48, 48, 50, 52, 54, 54, 54, 56, 58, 58, 60, 62, 62, 62, 62, 64, 64, 64
Offset: 0

Views

Author

Antti Karttunen, Apr 18 2014

Keywords

Comments

All terms are even. Used by the "number-of-runs beanstalk" sequence A255056 and many of its associated sequences.

Crossrefs

Cf. A091067 (the positions of records), A106836 (run lengths).
Cf. A255070 (terms divided by 2).

Programs

  • Maple
    A236840 := proc(n) local i, b; if n=0 then 0 else b := convert(n, base, 2); select(i -> (b[i-1]<>b[i]), [$2..nops(b)]); n-1-nops(%) fi end: seq(A236840(i), i=0..69); # Peter Luschny, Apr 19 2014
  • Mathematica
    a[n_] := n - Length@ Split[IntegerDigits[n, 2]]; a[0] = 0; Array[a, 100, 0] (* Amiram Eldar, Jul 16 2023 *)
  • Scheme
    (define (A236840 n)  (- n (A005811 n)))

Formula

a(n) = n - A005811(n) = n - A000120(A003188(n)).
a(n) = 2*A255070(n).

A244232 Sum of "digit values" in Semigreedy Catalan Representation of n, A244159.

Original entry on oeis.org

0, 1, 1, 2, 3, 1, 2, 2, 3, 4, 4, 5, 6, 4, 1, 2, 2, 3, 4, 2, 3, 3, 4, 5, 5, 6, 7, 5, 6, 6, 7, 8, 8, 9, 10, 8, 5, 6, 6, 7, 8, 6, 1, 2, 2, 3, 4, 2, 3, 3, 4, 5, 5, 6, 7, 5, 2, 3, 3, 4, 5, 3, 4, 4, 5, 6, 6, 7, 8, 6, 7, 7, 8, 9, 9, 10, 11, 9, 6, 7, 7, 8, 9, 7, 8, 8, 9, 10, 10, 11, 12, 10, 11, 11, 12, 13, 13, 14, 15, 13, 10, 11, 11, 12, 13, 11, 6, 7, 7, 8, 9, 7, 8, 8, 9, 10, 10, 11, 12, 10, 7, 8, 8, 9, 10, 8, 9, 9, 10, 11, 11, 12, 1
Offset: 0

Views

Author

Antti Karttunen, Jun 25 2014

Keywords

Comments

Note that a(33604) = A000217(10) = 55 because the sum is computed from the underlying list (vector) of numbers, and thus is not subject to any corruption by decimal representation as A244159 itself is.
Equivalent description: partition n "greedily" as terms of A197433, i.e. n = A197433(i) + A197433(j) + ... + A197433(k), always using the largest term of A197433 that still "fits in" (i.e. is <= n remaining). Then a(n) = A000120(i) + A000120(j) + ... + A000120(k).

Examples

			For n=18, using the alternative description, we see that it is partitioned  into the terms of A197433 as a greedy sum A197433(11) + A197433(1) = 17 + 1. Thus a(18) = A000120(11) + A000120(1) = 3+1 = 4.
For n=128, we see that is likewise represented as A197433(31) + A197433(31) = 64 + 64. Thus a(128) = 2*A000120(31) = 10.
		

Crossrefs

Formula

If A176137(n) = 1, a(n) = A000120(A244230(n)), otherwise a(n) = A000120(A244230(n)-1) + a(n-A197433(A244230(n)-1)).
For all n, a(A000108(n)) = 1. [And moreover, Catalan numbers, A000108, give all such k that a(k) = 1].
For all n, a(A014138(n)) = n and a(A014143(n)) = A000217(n+1).

A244320 a(n) = n - A014420(n).

Original entry on oeis.org

0, 0, 1, 1, 2, 4, 4, 5, 5, 6, 8, 8, 9, 9, 13, 13, 14, 14, 15, 17, 17, 18, 18, 19, 21, 21, 22, 22, 26, 26, 27, 27, 28, 30, 30, 31, 31, 32, 34, 34, 35, 35, 41, 41, 42, 42, 43, 45, 45, 46, 46, 47, 49, 49, 50, 50, 54, 54, 55, 55, 56, 58, 58, 59, 59, 60, 62, 62, 63, 63, 67, 67, 68, 68, 69
Offset: 0

Views

Author

Antti Karttunen, Jul 02 2014

Keywords

Crossrefs

Programs

Formula

a(n) = n - A014420(n).
Showing 1-3 of 3 results.