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.

A277710 Square array A(r,c), where each row r lists all numbers k for which A264977(k) = r, read by downwards antidiagonals: A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), etc.

Original entry on oeis.org

1, 5, 2, 13, 10, 3, 29, 26, 39, 4, 41, 58, 75, 20, 9, 61, 82, 147, 52, 21, 6, 85, 122, 207, 116, 45, 78, 7, 125, 170, 291, 164, 93, 150, 11, 8, 173, 250, 411, 244, 189, 294, 19, 40, 81, 209, 346, 579, 340, 381, 414, 35, 104, 105, 18, 253, 418, 819, 500, 657, 582, 67, 232, 165, 42, 23, 281, 506, 927, 692, 765, 822, 131, 328, 213, 90, 43, 12
Offset: 1

Views

Author

Antti Karttunen, Oct 29 2016

Keywords

Comments

Alternative description: Each row r lists the positions of A019565(r) in A277330.
Odd terms occur only on rows with odd index, and even terms only on rows with even index. Specifically: all terms k on row r are equal to r modulo 4, thus the first differences of each row are all multiples of 4.
All the terms on any particular row are either all multiples of two (or respectively: three, or six), or none of them are.

Examples

			The top left 12 x 12 corner of the array:
   1,   5,  13,  29,  41,   61,   85,  125,  173,  209,  253,  281
   2,  10,  26,  58,  82,  122,  170,  250,  346,  418,  506,  562
   3,  39,  75, 147, 207,  291,  411,  579,  819,  927, 1155, 1635
   4,  20,  52, 116, 164,  244,  340,  500,  692,  836, 1012, 1124
   9,  21,  45,  93, 189,  381,  657,  765,  873, 1317, 1533, 1749
   6,  78, 150, 294, 414,  582,  822, 1158, 1638, 1854, 2310, 3270
   7,  11,  19,  35,  67,  131,  259,  311,  359,  515,  619,  655
   8,  40, 104, 232, 328,  488,  680, 1000, 1384, 1672, 2024, 2248
  81, 105, 165, 213, 333,  429,  669,  861, 1341, 1725, 2685, 2721
  18,  42,  90, 186, 378,  762, 1314, 1530, 1746, 2634, 3066, 3498
  23,  43,  79,  83, 103,  155,  163,  203,  307,  323,  403,  611
  12, 156, 300, 588, 828, 1164, 1644, 2316, 3276, 3708, 4620, 6540
		

Crossrefs

Transpose: A277709.
Column 1: A277711, sorted into ascending order: A277817.
Row 1: A277701, Row 2: A277712 (= 2*A277701), Row 3: A277713, Row 4: 4*A277701, Row 5: A277715, Row 6: 2*A277713. Row 8: 8*A277701, Row 10: 2*A277715.
Cf. A277824 (the index of the column where n is located in this array).
Cf. A019565, A264977, A277330, A277816 and permutation pair A277695 & A277696.

Formula

A(r,1) = A277711(r); for c > 1, A(r,c) = A277816(A(r,c-1)).
Other identities. For all r>=1, c>=1:
A(2*r,c) = 2*A(r,c).
A(r,c) modulo 4 = r modulo 4.

Extensions

The dispersion-style formula added by Antti Karttunen, Nov 06 2016

A277817 Positions of zeros in A277815; sequence A277711 sorted into ascending order.

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 7, 8, 9, 12, 14, 15, 16, 17, 18, 23, 24, 28, 30, 31, 32, 33, 34, 36, 46, 47, 48, 49, 56, 60, 62, 63, 64, 65, 66, 68, 72, 73, 81, 87, 92, 94, 95, 96, 97, 98, 111, 112, 120, 124, 126, 127, 128, 129, 130, 132, 135, 136, 137, 143, 144, 145, 146, 153, 159, 162, 174, 175, 177, 184, 188, 190, 191, 192, 193, 194, 196, 222
Offset: 0

Views

Author

Antti Karttunen, Nov 06 2016

Keywords

Comments

Numbers n for which there is no such k < n that A264977(k) = A264977(n).
After zero, numbers not in the range of A277816.

Crossrefs

Sequence A277711 sorted into ascending order.
Positions of ones in A277824.
Cf. A277884 (a left inverse).

Formula

Other identities. For all n >= 0:
A277884(a(n)) = n.

A277816 a(n) = the least k > n for which A264977(k) = A264977(n), or 0 if no such k exists.

Original entry on oeis.org

0, 5, 10, 39, 20, 13, 78, 11, 40, 21, 26, 19, 156, 29, 22, 27, 80, 25, 42, 35, 52, 45, 38, 43, 312, 37, 58, 51, 44, 41, 54, 59, 160, 57, 50, 67, 84, 53, 70, 75, 104, 61, 90, 79, 76, 93, 86, 55, 624, 101, 74, 99, 116, 77, 102, 71, 88, 69, 82, 115, 108, 85, 118, 123, 320, 121, 114, 131, 100, 117, 134, 91, 168, 89, 106, 147, 140, 109, 150, 83, 208, 105
Offset: 0

Views

Author

Antti Karttunen, Nov 06 2016

Keywords

Crossrefs

Cf. A277815 (a left inverse).
Cf. A277701, A277712, A277713, A277715 (iterates of this sequence starting from 1, 2, 3 and 9 respectively).

Programs

  • Scheme
    (define (A277816 n) (if (zero? n) n (let ((v (A264977 n))) (let loop ((k (+ 1 n))) (if (= v (A264977 k)) k (loop (+ 1 k)))))))

Formula

For all n >= 0, A277815(a(n)) = n.

A277695 Permutation of natural numbers: a(1) = 1; for n > 1, if A277815(n) = 0, a(n) = 2*a(A277814(n)-1), otherwise a(n) = 1 + 2*a(A277815(n)).

Original entry on oeis.org

1, 2, 4, 8, 3, 16, 6, 32, 12, 5, 13, 64, 7, 24, 10, 26, 128, 14, 27, 17, 25, 49, 48, 20, 257, 11, 21, 52, 15, 256, 28, 54, 34, 50, 55, 98, 515, 99, 9, 65, 31, 29, 97, 105, 51, 96, 40, 514, 22, 101, 43, 35, 1031, 513, 81, 42, 69, 23, 57, 104, 63, 30, 512, 56, 108, 68, 111, 100, 139, 199, 163, 110, 196, 203, 19, 211, 2063, 33, 195, 53, 1030, 47
Offset: 1

Views

Author

Antti Karttunen, Nov 06 2016

Keywords

Crossrefs

Formula

a(1) = 1; for n > 1, if A277815(n) = 0 [when n is in A277817], a(n) = 2*a(A277814(n)-1), otherwise a(n) = 1 + 2*a(A277815(n)).
a(1) = 1, a(A277817(1+n)) = 2*a(n), a(A277816(n)) = 1 + 2*a(n). [Implicit form.]

A285112 Permutation of natural numbers: a(0) = 1, a(1) = 2, a(2n) = A005117(1+a(n)), a(2n+1) = A065642(a(n)).

Original entry on oeis.org

1, 2, 3, 4, 5, 9, 6, 8, 7, 25, 14, 27, 10, 12, 13, 16, 11, 49, 39, 125, 22, 28, 42, 81, 15, 20, 19, 18, 21, 169, 26, 32, 17, 121, 79, 343, 65, 117, 205, 625, 35, 44, 43, 56, 69, 84, 133, 243, 23, 45, 33, 40, 31, 361, 30, 24, 34, 63, 277, 2197, 41, 52, 53, 64, 29, 289, 199, 1331, 130, 6241, 563, 2401, 106, 325, 193, 351, 335, 1025, 1030, 3125, 58
Offset: 0

Views

Author

Antti Karttunen, Apr 17 2017

Keywords

Comments

Note the indexing: the domain starts from 0, while the range excludes zero.
This sequence can be represented as a binary tree. Each left hand child is produced as A005117(1+n), and each right hand child as A065642(n), when the parent node contains n >= 2:
1
|
...................2...................
3 4
5......../ \........9 6......../ \........8
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
7 25 14 27 10 12 13 16
11 49 39 125 22 28 42 81 15 20 19 18 21 169 26 32
etc.

Crossrefs

Inverse: A285111.
Similar or related permutations: A243344, A243346, A252753, A277696, A284572.
Cf. also arrays A284457 & A284311.

Formula

a(0) = 1, a(1) = 2, a(2n) = A005117(1+a(n)), a(2n+1) = A065642(a(n)).

A284572 Permutation of natural numbers: a(1) = 1, a(2n) = A005117(1+a(n)), a(2n+1) = A065642(1+a(n)).

Original entry on oeis.org

1, 2, 4, 3, 9, 6, 25, 5, 8, 14, 20, 10, 49, 39, 52, 7, 12, 13, 27, 22, 45, 33, 63, 15, 121, 79, 80, 65, 50, 85, 2809, 11, 16, 19, 169, 21, 28, 42, 56, 35, 529, 73, 92, 55, 68, 103, 128, 23, 32, 199, 244, 130, 100, 131, 243, 106, 132, 82, 153, 139, 172, 4619, 5620, 17, 18, 26, 289, 31, 40, 277, 340, 34, 44, 43, 841, 69, 1849, 91, 171, 58, 48
Offset: 1

Views

Author

Antti Karttunen, Apr 17 2017

Keywords

Comments

This sequence can be represented as a binary tree. Each left hand child is produced as A005117(1+n), and each right hand child as A065642(1+n), when the parent node contains n:
1
................../ \..................
2 4
3......../ \........9 6......../ \........25
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
5 8 14 20 10 49 39 52
7 12 13 27 22 45 33 63 15 121 79 80 65 50 85 2809
etc.
Compare to A285112.

Crossrefs

Inverse: A284571.
Similar or related permutations: A243344, A243346, A277696, A285112.

Formula

a(1) = 1, a(2n) = A005117(1+a(n)), a(2n+1) = A065642(1+a(n)).
Showing 1-6 of 6 results.