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.

A372356 Array read by upward antidiagonals: A(n, k) = A372354(1+n,k)-A372354(n,k), n,k >= 1.

Original entry on oeis.org

4, 8, 3, 16, 8, 6, 32, 16, 12, 3, 64, 32, 24, 5, 3, 128, 64, 48, 9, 7, 3, 256, 128, 96, 21, 13, 5, 5, 512, 256, 192, 44, 25, 13, 12, 3, 1024, 512, 384, 88, 53, 28, 24, 5, 3, 2048, 1024, 768, 176, 108, 56, 48, 8, 9, 2, 4096, 2048, 1536, 352, 216, 112, 96, 21, 20, 7, 8, 8192, 4096, 3072, 704, 432, 224, 192, 44, 40, 13, 16, 3
Offset: 1

Views

Author

Antti Karttunen, Apr 30 2024

Keywords

Examples

			Array begins:
n\k|    1     2     3    4    5    6     7    8     9   10    11   12   13   14
---+-----------------------------------------------------------------------------
1  |    4,    3,    6,   3,   3,   3,    5,   3,    3,   2,    8,   3,   4,   3,
2  |    8,    8,   12,   5,   7,   5,   12,   5,    9,   7,   16,   4,   6,   5,
3  |   16,   16,   24,   9,  13,  13,   24,   8,   20,  13,   32,  13,  15,  11,
4  |   32,   32,   48,  21,  25,  28,   48,  21,   40,  25,   64,  28,  29,  21,
5  |   64,   64,   96,  44,  53,  56,   96,  44,   80,  53,  128,  56,  57,  40,
6  |  128,  128,  192,  88, 108, 112,  192,  88,  160, 108,  256, 112, 117,  81,
7  |  256,  256,  384, 176, 216, 224,  384, 176,  320, 216,  512, 224, 236, 161,
8  |  512,  512,  768, 352, 432, 448,  768, 352,  640, 432, 1024, 448, 472, 324,
9  | 1024, 1024, 1536, 704, 864, 896, 1536, 704, 1280, 864, 2048, 896, 944, 647,
		

Crossrefs

Columnwise first differences of A372354.

Programs

A372282 Array read by upward antidiagonals: A(n, k) = A371094(A(n-1, k)) for n > 1, k >= 1; A(1, k) = 2*k-1.

Original entry on oeis.org

1, 21, 3, 5461, 21, 5, 357913941, 5461, 341, 7, 1537228672809129301, 357913941, 1398101, 45, 9, 28356863910078205288614550619314017621, 1537228672809129301, 23456248059221, 1109, 117, 11, 9649340769776349618630915417390658987772498722136713669954798667326094136661, 28356863910078205288614550619314017621, 6602346876188694799461995861, 873813, 11605, 69, 13
Offset: 1

Views

Author

Antti Karttunen, Apr 28 2024

Keywords

Examples

			Array begins:
n\k|    1     2        3     4      5     6        7     8      9     10
---+----------------------------------------------------------------------
1  |    1,    3,       5,    7,     9,   11,      13,   15,    17,    19,
2  |   21,   21,     341,   45,   117,   69,     341,   93,   213,   117,
3  | 5461, 5461, 1398101, 1109, 11605, 3413, 1398101, 2261, 87381, 11605,
		

Crossrefs

Cf. A005408 (row 1), A372351 (row 2, bisection of A371094), A372444 (column 14).
Arrays derived from this one:
A372285 the number of terms of A086893 in the interval [A(n, k), A(1+n, k)],
A372287 the column index of A(n, k) in array A257852,
A372288 the sum of digits of A(n, k) in "Jacobsthal greedy base",
A372353 differences between A(n,k) and the largest term of A086893 <= A(n,k),
A372354 floor(log_2(.)) of terms, A372356 (and their columnwise first differences),
A372359 terms xored with binary words of the same length, either of the form 10101...0101 or 110101...0101, depending on whether the binary length is odd or even.
Cf. also arrays A371096, A371102 that give subsets of columns of this array, and array A371100 that gives the terms of the row 2 in different order.

Programs

  • PARI
    up_to = 28;
    A371094(n) = { my(m=1+3*n, e=valuation(m,2)); ((m*(2^e)) + (((4^e)-1)/3)); };
    A372282sq(n,k) = if(1==n,2*k-1,A371094(A372282sq(n-1,k)));
    A372282list(up_to) = { my(v = vector(up_to), i=0); for(a=1,oo, for(col=1,a, i++; if(i > up_to, return(v)); v[i] = A372282sq((a-(col-1)),col))); (v); };
    v372282 = A372282list(up_to);
    A372282(n) = v372282[n];

A372449 a(n) = A000523(A372444(n)); One less than the length of binary expansion of the n-th iterate of 27 with A371094.

Original entry on oeis.org

4, 7, 12, 23, 44, 84, 165, 326, 650, 1297, 2590, 5177, 10349, 20695, 41386, 82766, 165527, 331048, 662093, 1324181, 2648358, 5296712, 10593418, 21186832, 42373658, 84747311, 169494616, 338989224, 677978441, 1355956875, 2711913744, 5423827481, 10847654953, 21695309901, 43390619796, 86781239588, 173562479173, 347124958346
Offset: 0

Views

Author

Antti Karttunen, May 04 2024

Keywords

Crossrefs

Programs

Formula

a(n) = A000523(A372444(n)).
a(0) = A372447(0) = 4, and for n > 0, a(n) = A372447(n) + 2*A372448(n-1).

A372359 Array read by upward antidiagonals: A(n, k) = A372358(A372282(n, k)), n,k >= 1.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 24, 4, 0, 0, 0, 256, 32, 6, 0, 0, 0, 0, 6144, 16, 0, 0, 0, 0, 0, 16777216, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 8, 4, 0, 0, 0, 0, 0, 0, 0, 1408, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6144, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16777216, 0, 88, 12
Offset: 1

Views

Author

Antti Karttunen, May 01 2024

Keywords

Comments

Zeros occur in the same locations as where they occur in A372353 and where 1's occur in array A372287.

Examples

			Array begins:
n\k| 1  2  3    4     5   6  7     8  9    10 11  12         13             14
---+----------------------------------------------------------------------------
1  | 0, 0, 0,   2,    4,  6, 0,    2, 4,    6, 0,  2,        12,            14,
2  | 0, 0, 0,  24,   32, 16, 0,    8, 0,   32, 0, 88,        96,           112,
3  | 0, 0, 0, 256, 6144,  0, 0, 1408, 0, 6144, 0,  0,      8192,          2560,
4  | 0, 0, 0,   0, 2^24,  0, 0,    0, 0, 2^24, 0,  0, 402653184,       6815744,
5  | 0, 0, 0,   0,    0,  0, 0,    0, 0,    0, 0,  0,      2^56, 4947802324992,
6  | 0, 0, 0,   0,    0,  0, 0,    0, 0,    0, 0,  0,         0,     31 * 2^79,
where 2^56 = 72057594037927936 and 31 * 2^79 = 18738350204026752207945728.
		

Crossrefs

Cf. also A372353.

Programs

Formula

A(n, k) = A372282(n,k) XOR A086893(1+A372354(n, k)), where XOR is bitwise-xor, A003987.

A372360 Array read by upward antidiagonals: A(n, k) = A000120(A372361(n, k)), n,k >= 1; Binary weights of terms of arrays A372359 and A372361.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 1, 0, 0, 0, 1, 1, 2, 0, 0, 0, 0, 2, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 3, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3
Offset: 1

Views

Author

Antti Karttunen, May 01 2024

Keywords

Comments

Entry A(n, k) at row n and column k tells how many bits needs to be flipped in the binary expansion of the (n-1)-th iterate of Reduced Collatz function R, when started from 2*k-1, to obtain the unique term of A086893 with the same binary length as that (n-1)-th iterate. That is, A(n, k) gives the Hamming distance between A372283(n, k) and A086893(1+A000523(A372283(n, k))).
Zeros occur in the same locations as where they occur in A372359, etc.

Examples

			Array begins:
n\k| 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
---+-------------------------------------------------------------------------
1  | 0, 0, 0, 1, 1, 2, 0, 1, 1, 2, 0, 1, 2, 3, 1, 2, 2, 3, 1, 2, 3, 4, 2, 3,
2  | 0, 0, 0, 2, 1, 1, 0, 1, 0, 1, 0, 3, 2, 3, 2, 3, 2, 0, 1, 3, 2, 2, 1, 2,
3  | 0, 0, 0, 1, 2, 0, 0, 3, 0, 2, 0, 0, 1, 2, 1, 2, 2, 0, 2, 2, 3, 1, 0, 5,
4  | 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 2, 3, 0, 5, 1, 0, 1, 3, 2, 1, 0, 4,
5  | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 4, 2, 0, 0, 2, 5, 1, 0, 3,
6  | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 3, 1, 0, 0, 2, 4, 2, 0, 3,
7  | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 3, 0, 0, 0, 1, 3, 1, 0, 4,
8  | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 4, 0, 0, 0, 2, 3, 0, 0, 3,
9  | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 3, 0, 0, 0, 1, 4, 0, 0, 4,
10 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 4, 0, 0, 0, 0, 3, 0, 0, 4,
11 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 4, 0, 0, 0, 0, 4, 0, 0, 5,
12 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 5, 0, 0, 0, 0, 4, 0, 0, 3,
13 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 3, 0, 0, 0, 0, 5, 0, 0, 6,
14 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 6, 0, 0, 0, 0, 3, 0, 0, 2,
15 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 2, 0, 0, 0, 0, 6, 0, 0, 4,
16 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 4, 0, 0, 0, 0, 2, 0, 0, 4,
17 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 4, 0, 0, 0, 0, 4, 0, 0, 4,
18 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 4, 0, 0, 0, 0, 4, 0, 0, 3,
19 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 3, 0, 0, 0, 0, 4, 0, 0, 4,
20 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 4, 0, 0, 0, 0, 3, 0, 0, 6,
21 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 6, 0, 0, 0, 0, 4, 0, 0, 4,
We have A372283(5, 14) = 71, and when we compare the binary expansion of 71 = 1000111_2 with the term of A086893 that has a binary expansion of the same length, which in this case is 85 = 1010101_2, we see that only the bits at positions 1 and 4 (indexed from the right hand end, with 0 being the least significant bit position at right) need to be toggled to obtain the 71 from 85 or vice versa, therefore A(5, 14) = 2.
We have A372283(6, 14) = 107 = 1101011_2, and when xored with A086893(7) = 85 = 1010101_2, we obtain A372361(6, 14) = 62 = 111110_2, with five 1-bits, therefore A(6, 14) = 5. I.e., five bits (all except the least and the most significant bit) need to be flipped to change 85 to 107 or vice versa.
		

Crossrefs

Binary weights of A372359 and A372361.
Cf. also A372288.

Programs

Formula

A(n, k) = A000120(A372361(n, k)) = A000120(A372358(A372283(n, k))).
A(n, k) = A000120(A372359(n, k)) = A000120(A372358(A372282(n, k))).

A372357 Array read by upward antidiagonals: A(n, k) = A372356(1+n,k)-2*A372356(n,k), n,k >= 1.

Original entry on oeis.org

0, 0, 2, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, -1, 1, 0, 0, 0, 3, -1, -1, 0, 0, 0, 2, -1, 3, 2, 0, 0, 0, 0, 3, 2, 0, -1, 0, 0, 0, 0, 2, 0, 0, -2, 3, 0, 0, 0, 0, 0, 0, 0, 5, 2, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 5, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 3, -1
Offset: 1

Views

Author

Antti Karttunen, Apr 30 2024

Keywords

Examples

			Array begins:
n\k| 1  2  3   4   5   6  7   8  9  10 11  12  13  14  15  16  17 18  19  20  21
---+-----------------------------------------------------------------------------
1  | 0, 2, 0, -1,  1, -1, 2, -1, 3,  3, 0, -2, -2, -1, -1, -1,  2, 5,  1,  1,  1,
2  | 0, 0, 0, -1, -1,  3, 0, -2, 2, -1, 0,  5,  3,  1, -1, -2, -2, 2, -1,  0, -1,
3  | 0, 0, 0,  3, -1,  2, 0,  5, 0, -1, 0,  2, -1, -1,  3,  1,  3, 0, -1, -2, -2,
4  | 0, 0, 0,  2,  3,  0, 0,  2, 0,  3, 0,  0, -1, -2,  2, -1, -1, 0,  3,  4,  1,
5  | 0, 0, 0,  0,  2,  0, 0,  0, 0,  2, 0,  0,  3,  1,  0,  2, -1, 0,  2, -2, -1,
6  | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  2, -1,  0, -1,  3, 0,  0,  3,  2,
7  | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0,  2,  0, -1,  2, 0,  0, -1, -1,
8  | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -1,  0,  1,  0, 0,  0, -1, -1,
9  | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -1,  0, -2,  0, 0,  0,  3,  1,
10 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0,  1,  0,  2,  0, 0,  0,  2, -2,
11 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -2,  0, -1,  0, 0,  0,  0,  2,
12 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0,  2,  0, -2,  0, 0,  0,  0, -1,
13 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -1,  0,  1,  0, 0,  0,  0, -2,
14 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -2,  0, -1,  0, 0,  0,  0,  1,
15 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0,  1,  0,  3,  0, 0,  0,  0, -1,
16 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -1,  0, -2,  0, 0,  0,  0,  3,
17 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0,  3,  0,  1,  0, 0,  0,  0, -2,
18 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -2,  0,  0,  0, 0,  0,  0,  1,
19 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0,  1,  0, -2,  0, 0,  0,  0,  0,
20 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0,  0,  0,  2,  0, 0,  0,  0, -2,
21 | 0, 0, 0,  0,  0,  0, 0,  0, 0,  0, 0,  0,  0, -2,  0, -2,  0, 0,  0,  0,  2,
		

Crossrefs

Programs

Showing 1-6 of 6 results.