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 1-6 of 6 results.

A151779 a(1)=1; for n > 1, a(n)=6*5^{wt(n-1)-1}.

Original entry on oeis.org

1, 6, 6, 30, 6, 30, 30, 150, 6, 30, 30, 150, 30, 150, 150, 750, 6, 30, 30, 150, 30, 150, 150, 750, 30, 150, 150, 750, 150, 750, 750, 3750, 6, 30, 30, 150, 30, 150, 150, 750, 30, 150, 150, 750, 150, 750, 750, 3750, 30, 150, 150, 750, 150, 750, 750, 3750, 150, 750, 750, 3750
Offset: 1

Views

Author

N. J. A. Sloane, Jun 25 2009

Keywords

Comments

Number of cells turned ON in n-th generation of cellular automaton based on Z^3 lattice in the same way that A147562 is based on the Z^2 lattice. Here each cell has six neighbors.

Crossrefs

Programs

  • Maple
    wt := proc(n) local w,m,i; w := 0; m := n; while m > 0 do i := m mod 2; w := w+i; m := (m-i)/2; od; w; end:
    f:=d->[seq((2*d)*(2*d-1)^(wt(n-1)-1),n=2..120)];
    f2:=d->[1,op(f(d))];
    f2(3);
  • PARI
    a(n)=6*5^(hammingweight(n-1)-1)\1 \\ Charles R Greathouse IV, Mar 07 2015

A255741 Square array read by antidiagonals upwards: T(n,k), n>=1, k>=1, in which row n lists the partial sums of the n-th row of the square array of A255740.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 5, 3, 1, 1, 5, 7, 7, 4, 1, 1, 6, 9, 13, 9, 4, 1, 1, 7, 11, 21, 16, 11, 4, 1, 1, 8, 13, 31, 25, 22, 13, 4, 1, 1, 9, 15, 43, 36, 37, 28, 15, 5, 1, 1, 10, 17, 57, 49, 56, 49, 40, 17, 5, 1, 1, 11, 19, 73, 64, 79, 76, 85, 43, 19, 5, 1, 1, 12, 21, 91, 81, 106, 109, 156, 89, 49, 21, 5, 1
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Examples

			The corner of the square array with the first 15 terms of the first 12 rows looks like this:
-------------------------------------------------------------------------
A000012: 1, 1, 1,  1,  1,  1,  1,   1,   1,   1,   1,   1,   1,   1,   1
A070941: 1, 2, 3,  3,  4,  4,  4,   4,   5,   5,   5,   5,   5,   5,   5
A005408: 1, 3, 5,  7,  9, 11, 13,  15,  17,  19,  21,  23,  25,  27,  29
A151788: 1, 4, 7, 13, 16, 22, 28,  40,  43,  49,  55,  67,  73,  85,  97
A147562: 1, 5, 9, 21, 25, 37, 49,  85,  89, 101, 113, 149, 161, 197, 233
A151790: 1, 6,11, 31, 36, 56, 76, 156, 161, 181, 201, 281, 301, 381, 461
A151781: 1, 7,13, 43, 49, 79,109, 259, 265, 295, 325, 475, 505, 655, 805
A151792: 1, 8,15, 57, 64,106,148, 400, 407, 449, 491, 743, 785,1037,1289
A151793: 1, 9,17, 73, 81,137,193, 585, 593, 649, 705,1097,1153,1545,1937
A255764: 1,10,19, 91,100,172,244, 820, 829, 901, 973,1549,1621,2197,2773
A255765: 1,11,21,111,121,211,301,1111,1121,1211,1301,2111,2201,3011,3821
A255766: 1,12,23,133,144,254,364,1464,1475,1585,1695,2795,2905,4005,5105
...
		

Crossrefs

A255764 Partial sums of A255743.

Original entry on oeis.org

1, 10, 19, 91, 100, 172, 244, 820, 829, 901, 973, 1549, 1621, 2197, 2773, 7381, 7390, 7462, 7534, 8110, 8182, 8758, 9334, 13942, 14014, 14590, 15166, 19774, 20350, 24958, 29566, 66430, 66439, 66511, 66583, 67159, 67231, 67807, 68383, 72991, 73063, 73639, 74215
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255741.

Crossrefs

Programs

  • Mathematica
    Accumulate@ MapAt[Floor, Array[9*8^(DigitCount[# - 1, 2, 1] - 1) &, 43], 1] (* Michael De Vlieger, Nov 03 2022 *)
  • PARI
    lista(nn) = {s = 1; for (n=2, nn, print1(s, ", "); s += 9*8^(hammingweight(n-1)-1););} \\ Michel Marcus, Mar 15 2015

Extensions

More terms from Michel Marcus, Mar 15 2015

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

A255766 Partial sums of A255745.

Original entry on oeis.org

1, 12, 23, 133, 144, 254, 364, 1464, 1475, 1585, 1695, 2795, 2905, 4005, 5105, 16105, 16116, 16226, 16336, 17436, 17546, 18646, 19746, 30746, 30856, 31956, 33056, 44056, 45156, 56156, 67156, 177156, 177167, 177277, 177387, 178487, 178597, 179697, 180797, 191797
Offset: 1

Views

Author

Omar E. Pol, Mar 05 2015

Keywords

Comments

Also, this is a row of the square array A255741.

Crossrefs

Programs

  • PARI
    a(n) = sum(k=1, n, if (k==1, 1, 11*10^(hammingweight(k-1)-1)));

Extensions

More terms from Michel Marcus, Mar 19 2015

A186410 Number of "ON" cells at n-th stage of three-dimensional version of the cellular automaton A183060 using cubes.

Original entry on oeis.org

0, 1, 6, 11, 32, 37, 58, 79, 180, 185, 206, 227, 328, 349, 450, 551, 1052, 1057, 1078, 1099, 1200, 1221, 1322, 1423, 1924, 1945, 2046, 2147, 2648, 2749, 3250, 3751, 6252, 6257, 6278, 6299, 6400, 6421, 6522, 6623
Offset: 0

Views

Author

Omar E. Pol, Feb 21 2011

Keywords

Comments

The sequence gives the total number of cells turned ON after n stages in a cellular automaton based on Z^3 lattice in the same way that A183060 is based on the Z^2 lattice. In general here each cell has six neighbors.
It appears that after 2^k stages the structure resembles a pyramid. For the first differences see A186411.

Crossrefs

Programs

  • Mathematica
    a[n_] := n + (4/5) Sum[5^DigitCount[i, 2, 1], {i, n - 1}]; Array[a, 40, 0] (* Michael De Vlieger, Nov 02 2022 *)

Formula

From Nathaniel Johnston, Mar 14 2011: (Start)
a(n) = n + (4/5)*(Sum_{i=1..n-1} 5^A000120(i)).
a(2^n) = 2^n + (4/5)*(6^n - 1).
(End)

Extensions

More terms from Nathaniel Johnston, Mar 14 2011
Showing 1-6 of 6 results.