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 1-4 of 4 results.

A255765 Partial sums of A255744.

Original entry on oeis.org

1, 11, 21, 111, 121, 211, 301, 1111, 1121, 1211, 1301, 2111, 2201, 3011, 3821, 11111, 11121, 11211, 11301, 12111, 12201, 13011, 13821, 21111, 21201, 22011, 22821, 30111, 30921, 38211, 45501, 111111, 111121, 111211, 111301, 112111, 112201, 113011, 113821, 121111
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255741.
Is this sequence related to positive repunits? (see formula section).

Crossrefs

Programs

  • Mathematica
    Accumulate@ MapAt[Floor, Array[10*9^(DigitCount[# - 1, 2, 1] - 1) &, 40], 1] (* Michael De Vlieger, Nov 03 2022 *)
  • PARI
    lista(nn) = {s = 1; for (n=2, nn, print1(s, ", "); s += 10*9^(hammingweight(n-1)-1););} \\ Michel Marcus, Mar 15 2015
    
  • PARI
    a(n) = sum(k=1, n, if (k==1, 1, 10*9^(hammingweight(k-1)-1))); \\ Michel Marcus, Mar 15 2015

Formula

Question: a(2^k) = A002275(k+1), k >= 0. Is this true?

Extensions

More terms from Michel Marcus, Mar 15 2015

A255740 Square array read by antidiagonals upwards: T(n,1) = 1; for k > 1, T(n,k) = (n-1)*(n-2)^(A000120(k-1)-1) with n >= 1.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 2, 0, 0, 1, 4, 3, 2, 1, 0, 1, 5, 4, 6, 2, 0, 0, 1, 6, 5, 12, 3, 2, 0, 0, 1, 7, 6, 20, 4, 6, 2, 0, 0, 1, 8, 7, 30, 5, 12, 6, 2, 1, 0, 1, 9, 8, 42, 6, 20, 12, 12, 2, 0, 0, 1, 10, 9, 56, 7, 30, 20, 36, 3, 2, 0, 0, 1, 11, 10, 72, 8, 42, 30, 80, 4, 6, 2, 0, 0, 1, 12, 11, 90, 9, 56, 42, 150, 5, 12, 6, 2, 0, 0
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

The partial sums of row n give the n-th row of the square array A255741.

Examples

			The corner of the square array with the first 16 terms of the first 12 rows looks like this:
-------------------------------------------------------------------------
A000007: 1, 0, 0,  0, 0,  0,  0,   0, 0,  0,  0,   0,  0,   0,   0,    0
A255738: 1, 1, 1,  0, 1,  0,  0,   0  1,  0,  0,   0,  0,   0,   0,    0
A040000: 1, 2, 2,  2, 2,  2,  2,   2, 2,  2,  2,   2,  2,   2,   2,    2
A151787: 1, 3, 3,  6, 3,  6,  6,  12, 3,  6,  6,  12,  6,  12,  12,   24
A147582: 1, 4, 4, 12, 4, 12, 12,  36, 4, 12, 12,  36, 12,  36,  36,  108
A151789: 1, 5, 5, 20, 5, 20, 20,  80, 5, 20, 20,  80, 20,  80,  80,  320
A151779: 1, 6, 6, 30, 6, 30, 30, 150, 6, 30, 30, 150, 30, 150, 150,  750
A151791: 1, 7, 7, 42, 7, 42, 42, 252, 7, 42, 42, 252, 42, 252, 252, 1512
A151782: 1, 8, 8, 56, 8, 56, 56, 392, 8, 56, 56, 392, 56, 392, 392, 2744
A255743: 1, 9, 9, 72, 9, 72, 72, 576, 9, 72, 72, 576, 72, 576, 576, 4608
A255744: 1,10,10, 90,10, 90, 90, 810,10, 90, 90, 810, 90, 810, 810, 7290
A255745: 1,11,11,110,11,110,110,1100,11,110,110,1100,110,1100,1100,11000
...
		

Crossrefs

Column 1 is A000012.
Columns 2^k+1, for k >=0: A011477.
Columns 4, 6, 7, 10, 11, 13...: 0 together with A002378.

Programs

  • PARI
    tabl(nn) = {for (n=1, nn, for (k=1, nn, if (k==1, x = 1, x= (n-1)*(n-2)^(hammingweight(k-1)-1)); print1(x, ", ");); print(););} \\ Michel Marcus, Mar 15 2015

Formula

T(n,1) = 1; for k > 1, T(n,k) = (n-1)*(n-2)^(A000120(k-1)-1) with n >= 1.

A255743 a(1) = 1; for n > 1, a(n) = 9*8^{A000120(n-1)-1}.

Original entry on oeis.org

1, 9, 9, 72, 9, 72, 72, 576, 9, 72, 72, 576, 72, 576, 576, 4608, 9, 72, 72, 576, 72, 576, 576, 4608, 72, 576, 576, 4608, 576, 4608, 4608, 36864, 9, 72, 72, 576, 72, 576, 576, 4608, 72, 576, 576, 4608, 576, 4608, 4608, 36864, 72, 576, 576, 4608, 576, 4608, 4608
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255740.
Partial sums give A255764.

Examples

			Written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
   1;
   9;
   9, 72;
   9, 72, 72, 576;
   9, 72, 72, 576, 72, 576, 576, 4608;
   ...
		

Crossrefs

Programs

  • Mathematica
    MapAt[Floor, Array[9*8^(DigitCount[# - 1, 2, 1] - 1) &, 55], 1] (* Michael De Vlieger, Nov 03 2022 *)
  • PARI
    a(n) = if (n==1, 1, 9*8^(hammingweight(n-1)-1)); \\ Michel Marcus, Mar 15 2015
    
  • Python
    # Python 3.10+
    def A255743(n): return 1 if n == 1 else 9*(1<<((n-1).bit_count()-1)*3) # Chai Wah Wu, Nov 15 2022

Extensions

More terms from Michel Marcus, Mar 15 2015

A255745 a(1) = 1; for n > 1, a(n) = 11*10^{A000120(n-1)-1}.

Original entry on oeis.org

1, 11, 11, 110, 11, 110, 110, 1100, 11, 110, 110, 1100, 110, 1100, 1100, 11000, 11, 110, 110, 1100, 110, 1100, 1100, 11000, 110, 1100, 1100, 11000, 1100, 11000, 11000, 110000, 11, 110, 110, 1100, 110, 1100, 1100, 11000, 110, 1100, 1100, 11000, 1100, 11000, 11000
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255740.
Partial sums give A255766.
Is this also A151787 written in base 2?

Examples

			Also, written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
1;
11;
11, 110;
11, 110, 110, 1100;
11, 110, 110, 1100, 110, 1100, 1100, 11000;
...
		

Crossrefs

Programs

  • PARI
    a(n) = if (n==1, 1, 11*10^(hammingweight(n-1)-1)); \\ Michel Marcus, Mar 13 2015

Extensions

More terms from Michel Marcus, Mar 13 2015
Showing 1-4 of 4 results.