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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A343757 Irregular table read by rows; the n-th row contains the sums of distinct terms of the n-th row of table A343835, in ascending order.

Original entry on oeis.org

0, 0, 1, 0, 2, 0, 3, 0, 4, 0, 1, 4, 5, 0, 6, 0, 7, 0, 8, 0, 1, 8, 9, 0, 2, 8, 10, 0, 3, 8, 11, 0, 12, 0, 1, 12, 13, 0, 14, 0, 15, 0, 16, 0, 1, 16, 17, 0, 2, 16, 18, 0, 3, 16, 19, 0, 4, 16, 20, 0, 1, 4, 5, 16, 17, 20, 21, 0, 6, 16, 22, 0, 7, 16, 23, 0, 24
Offset: 0

Views

Author

Rémy Sigrist, May 01 2021

Keywords

Comments

In other words, the n-th row contains the numbers k whose runs of 1's in the binary expansion also appear in that of n.
The n-th row has 2^A069010(n) terms.
This sequence has similarities with A295989.

Examples

			Table begins:
     0:    [0]
     1:    [0, 1]
     2:    [0, 2]
     3:    [0, 3]
     4:    [0, 4]
     5:    [0, 1, 4, 5]
     6:    [0, 6]
     7:    [0, 7]
     8:    [0, 8]
     9:    [0, 1, 8, 9]
    10:    [0, 2, 8, 10]
    11:    [0, 3, 8, 11]
    12:    [0, 12]
    13:    [0, 1, 12, 13]
    14:    [0, 14]
    15:    [0, 15]
Table begins in binary:
       0:   [0]
       1:   [0, 1]
      10:   [0, 10]
      11:   [0, 11]
     100:   [0, 100]
     101:   [0, 1, 100, 101]
     110:   [0, 110]
     111:   [0, 111]
    1000:   [0, 1000]
    1001:   [0, 1, 1000, 1001]
    1010:   [0, 10, 1000, 1010]
    1011:   [0, 11, 1000, 1011]
    1100:   [0, 1100]
    1101:   [0, 1, 1100, 1101]
    1110:   [0, 1110]
    1111:   [0, 1111]
		

Crossrefs

Programs

  • PARI
    row(n) = { my (rr=[]); while (n, my (z=valuation(n, 2), o=valuation(n/2^z+1, 2), r=(2^o-1)*2^z); n-=r; rr = concat(rr, r)); vector(2^#rr, k, vecsum(vecextract(rr, k-1))) }

Formula

T(n, 0) = 0.
T(n, 1) = A342410(n) for any n > 0.
T(n, 2^A069010(n)-1) = n.

A356397 a(n) is the product of the terms in the n-th row of triangle A343835; a(0) = 1.

Original entry on oeis.org

1, 1, 2, 3, 4, 4, 6, 7, 8, 8, 16, 24, 12, 12, 14, 15, 16, 16, 32, 48, 64, 64, 96, 112, 24, 24, 48, 72, 28, 28, 30, 31, 32, 32, 64, 96, 128, 128, 192, 224, 256, 256, 512, 768, 384, 384, 448, 480, 48, 48, 96, 144, 192, 192, 288, 336, 56, 56, 112, 168, 60, 60, 62
Offset: 0

Views

Author

Rémy Sigrist, Aug 05 2022

Keywords

Examples

			For n = 11:
- row 11 of A343835 is (8, 3),
- so a(11) = 8 * 3 = 24.
		

Crossrefs

Programs

  • PARI
    a(n) = { my (v=1); while (n, my (z=valuation(n, 2), o=valuation(n/2^z+1, 2), r=(2^o-1)*2^z); n-=r; v*=r); v }

Formula

a(2*n) = a(n) * A277561(n).
a(n) = n iff n belongs to A023758 \ {0}.
A246674(n) divides a(n).
Showing 1-2 of 2 results.