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 1-10 of 15 results. Next

A269804 Numbers having harmonic fractility 1, cf. A270000.

Original entry on oeis.org

2, 3, 4, 6, 7, 8, 9, 12, 14, 16, 17, 18, 21, 24, 27, 28, 31, 32, 34, 36, 42, 48, 49, 51, 54, 56, 62, 63, 64, 68, 72, 81, 84, 93, 96, 98, 102, 108, 112, 113, 124, 126, 128, 136, 144, 147, 151, 153, 162, 168, 186, 189, 192, 196, 204, 216, 224, 226, 241, 243
Offset: 1

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In order to define (harmonic) fractility of an integer m > 1, we first define nested interval sequences. Suppose that r = (r(n)) is a sequence satisfying (i) 1 = r(1) > r(2) > r(3) > ... and (ii) r(n) -> 0. For x in (0,1], let n(1) be the index n such that r(n+1) < x <= r(n), and let L(1) = r(n(1)) - r(n(1)+1). Let n(2) be the largest index n such that x <= r(n(1)+1) + L(1)*r(n), and let L(2) = (r(n(2))-r(n(2)+1))*L(1). Continue inductively to obtain the sequence (n(1), n(2), n(3), ... ) =: NI(x), the r-nested interval sequence of x.
For fixed r, call x and y equivalent if NI(x) and NI(y) are eventually equal (up to an offset). For m > 1, the r-fractility of m is the number of equivalence classes of sequences NI(k/m) for 0 < k < m. Taking r = (1/1, 1/2, 1/3, 1/4, ...) gives harmonic fractility.
For harmonic fractility, r(n) = 1/n, n(j+1) = floor(L(j)/(x - Sum_{i=1..j} L(i-1)/(n(i)+1))) for all j >= 0, L(0) = 1. - M. F. Hasler, Nov 05 2018

Examples

			Nested-interval sequences NI(k/m) for m = 6:
NI(1/6) = (6, 1, 1, 1, 1, 1,...)
NI(2/6) = (3, 1, 1, 1, 1, 1,...)
NI(3/6) = (2, 1, 1, 1, 1, 1,...)
NI(4/6) = (1, 3, 1, 1, 1, 1,...)
NI(5/6) = (1, 1, 3, 1, 1, 1,...):
There is only one equivalence class, so that the fractility of 6 is 1.
		

Crossrefs

Cf. A269805, A269806, A269807, A269808, A269809 (numbers with harmonic fractility 2, ..., 6), A270000 (harmonic fractility of n).

Programs

Extensions

Edited by M. F. Hasler, Nov 05 2018

A269805 Numbers having harmonic fractility A270000(n) = 2.

Original entry on oeis.org

5, 10, 15, 20, 30, 37, 40, 43, 45, 59, 60, 61, 73, 74, 80, 85, 86, 90, 97, 101, 103, 107, 111, 118, 120, 122, 127, 129, 135, 139, 146, 148, 160, 167, 170, 172, 177, 180, 183, 194, 199, 202, 206, 214, 219, 222, 236, 240, 244, 254, 255, 258, 270, 277, 278, 291
Offset: 1

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Comments

In order to define (harmonic) fractility of an integer n > 1, we first define nested interval sequences. Suppose that r = (r(n)) is a sequence satisfying (i) 1 = r(1) > r(2) > r(3) > ... and (ii) r(n) -> 0. For x in (0,1], let n(1) be the index n such that r(n+1) < x <= r(n), and let L(1) = r(n(1))-r(n(1)+1). Let n(2) be the largest index n such that x <= r(n(1)+1) + L(1)*r(n), and let L(2) = (r(n(2))-r(n(2)+1))*L(1). Continue inductively to obtain the sequence (n(1), n(2), n(3), ... ) =: NI(x), the r-nested interval sequence of x.
For fixed r, call x and y equivalent if NI(x) and NI(y) are eventually equal (up to an offset). For n > 1, the r-fractility of n is the number of equivalence classes of sequences NI(m/n) for 0 < m < n. Taking r = (1/1, 1/2, 1/3, 1/4, ...) gives harmonic fractility.

Examples

			Nested interval sequences NI(k/m) for m = 5:
NI(1/5) = (5, 1, 1, 1, 1, 1,...),
NI(2/5) = (2, 2, 2, 2, 2, 2,...),
NI(3/5) = (1, 5, 1, 1, 1, 1,...),
NI(4/5) = (1, 1, 5, 1, 1, 1,...),
so that there are 2 equivalence classes for n = 5, and the fractility of 5 is 2.
		

Crossrefs

Cf. A269804, A269806, A269807, A269808, A269809 (numbers with harmonic fractility 1, 3, ..., 6), A270000 (harmonic fractility of n).

Programs

Extensions

Edited by M. F. Hasler, Nov 05 2018

A269806 Numbers having harmonic fractility A270000(n) = 3.

Original entry on oeis.org

11, 13, 19, 22, 23, 25, 26, 29, 33, 35, 38, 39, 44, 46, 47, 50, 52, 53, 57, 58, 66, 67, 69, 70, 75, 76, 78, 79, 83, 87, 88, 89, 92, 94, 99, 100, 104, 105, 106, 114, 116, 117, 119, 125, 132, 133, 134, 138, 140, 149, 150, 152, 155, 156, 158, 159, 161, 166, 171
Offset: 1

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Author

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Comments

To define (harmonic) fractility of an integer m > 1, we first define nested interval sequences. Suppose that r = (r(n)) is a sequence satisfying (i) 1 = r(1) > r(2) > r(3) > ... and (ii) r(n) -> 0. For x in (0,1], let n(1) be the index n such that r(n+1) < x <= r(n), and let L(1) = r(n(1)) - r(n(1)+1). Let n(2) be the largest index n such that x <= r(n(1)+1) + L(1)*r(n), and let L(2) = (r(n(2))-r(n(2)+1))*L(1). Continue inductively to obtain the sequence (n(1), n(2), n(3), ... ) =: NI(x), the r-nested interval sequence of x.
For fixed r, call x and y equivalent if NI(x) and NI(y) are eventually identical. For m > 1, the r-fractility of m is the number of equivalence classes of sequences NI(k/m) for 0 < k < m. Taking r = (1/1, 1/2, 1/3, 1/4, ...) gives harmonic fractility.
In the case of harmonic fractility, r(n) = 1/n, we have n(j+1) = floor(L(j)/(x -Sum_{i=1..j} L(i-1)/(n(i)+1))) for j >= 0, L(0) = 1. - M. F. Hasler, Nov 05 2018

Examples

			Nested interval sequences NI(k/m) for m = 11:
NI(1/11) = (11,1, 1, 1, 1, 1, 1, 1, ...),
NI(2/11) = (5, 2, 1, 2, 1, 2, 1, 1, 2, ...),
NI(3/11) = (3, 3, 3, 3, 3, 3, 3, 3, 3, ...),
NI(4/11) = (2, 5, 2, 1, 2, 1, 2, 1, 2, ...),
NI(5/11) = (2, 1, 2, 1, 2, 1, 2, 1, 2, ...) equivalent to NI(4/11),
NI(6/11) = (1, 11, 1, 1, 1, 1, 1, 1, ...) equivalent to NI(1/11),
NI(7/11) = (1, 3, 3, 3, 3, 3, 3, 3, 3, ...) equivalent to NI(3/11),
NI(8/11) = (1, 2, 1, 2, 1, 2, 1, 2, 1, ...) equivalent to NI(4/11),
NI(9/11) = (1, 1, 3, 3, 3, 3, 3, 3, 3, ...) equivalent to NI(3/11),
NI(10/11) = (1, 1, 1, 3, 3, 3, 3, 3, ...) equivalent to NI(3/11).
So there are 3 equivalence classes for m = 11, and the fractility of 11 is 3.
		

Crossrefs

Cf. A269804, A269805, A269807, A269808, A269809 (numbers with harmonic fractility 1, 2, 4, 5, 6, respectively); A270000 (harmonic fractility of n).

Programs

Extensions

Edited by M. F. Hasler, Nov 05 2018

A269807 Numbers having harmonic fractility A270000(n) = 4.

Original entry on oeis.org

41, 71, 82, 109, 123, 141, 142, 157, 163, 164, 169, 175, 179, 181, 187, 191, 197, 211, 218, 229, 246, 251, 257, 265, 271, 282, 284, 293, 305, 311, 314, 323, 326, 327, 328, 338, 341, 350, 358, 362, 369, 371, 374, 382, 394, 395, 415, 422, 423, 433, 436, 445, 449
Offset: 1

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Author

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Comments

In order to define (harmonic) fractility of an integer m > 1, we first define nested interval sequences. Suppose that r = (r(n)) is a sequence satisfying (i) 1 = r(1) > r(2) > r(3) > ... and (ii) r(n) -> 0. For x in (0,1], let n(1) be the index n such that r(n+1) < x <= r(n), and let L(1) = r(n(1)) - r(n(1)+1). Let n(2) be the largest index n such that x <= r(n(1)+1) + L(1)*r(n), and let L(2) = (r(n(2)) - r(n(2)+1))*L(1). Continue inductively to obtain the sequence (n(1), n(2), n(3), ...) =: NI(x), the r-nested interval sequence of x.
For fixed r, call x and y equivalent if NI(x) and NI(y) are eventually equal (up to an offset). For m > 1, the r-fractility of m is the number of equivalence classes of sequences NI(k/m) for 0 < k < m. Taking r = (1/1, 1/2, 1/3, 1/4, ... ) gives harmonic fractility.
In the case of harmonic fractility, r(n) = 1/n, we have n(j+1) = floor(L(j)/(x -Sum_{i=1..j} L(i-1)/(n(i)+1))) for j >= 0, L(0) = 1. - M. F. Hasler, Nov 05 2018

Examples

			Nested interval sequences NI(k/m) for m = 41:
NI(1/41) = (41, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...),
NI(2/41) = (20, 2, 1, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 1, 1, ...),
NI(3/41) = (13, 3, 1, 1, 4, 2, 2, 20, 1, 1, 1, 2, 2, 1, 1, 1, 2, ...) ~ NI(2/41),
NI(4/41) = (10, 1, 2, 1, 1, 8, 1, 1, 8, 1, 1, 8, 1, 1, 8, 1, 1, 8, 1, 1, ...),
NI(5/41) = (6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, ...).
Any further NI(k/41) is equivalent to one of the  above, e.g., NI(40/11) = (1, 1, 1, 1, 1, 4, 2, 2, 20, 2, 1, 1, 1, 2, 2, 1, 1, 1, 2, ...) ~ NI(2/41).
Thus, the number of equivalence classes is 4 (represented by 1/41, 2/41, 4/41 and 5/41), so that the fractility of 41 is 4.
		

Crossrefs

Cf. A269804, A269805, A269806, A269808, A269809 (numbers with harmonic fractility 1, 2, ..., 6), A270000 (harmonic fractility of n).

Programs

Extensions

More terms from Jack W Grahl, Jun 27 2018
Edited by M. F. Hasler, Nov 05 2018

A269808 Numbers having harmonic fractility A270000(n) = 5.

Original entry on oeis.org

55, 65, 91, 110, 115, 121, 130, 137, 165, 182, 195, 205, 213, 220, 221, 230, 235, 242, 260, 273, 274, 295, 330, 335, 337, 345, 355, 361, 363, 364, 390, 391, 403, 407, 410, 411, 419, 426, 440, 442, 460, 467, 470, 481, 484, 485, 495, 497, 503, 505, 517, 520, 546
Offset: 1

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Comments

In order to define (harmonic) fractility of an integer m > 1, we first define nested interval sequences. Suppose that r = (r(n)) is a sequence satisfying (i) 1 = r(1) > r(2) > r(3) > ... and (ii) r(n) -> 0. For x in (0,1], let n(1) be the index n such that r(n+1) < x <= r(n), and let L(1) = r(n(1)) - r(n(1)+1). Let n(2) be the largest index n such that x <= r(n(1)+1) + L(1)*r(n), and let L(2) = (r(n(2)) - r(n(2)+1))*L(1). Continue inductively to obtain the sequence (n(1), n(2), n(3), ...) =: NI(x), the r-nested interval sequence of x.
For fixed r, call x and y equivalent if NI(x) and NI(y) are eventually equal (up to an offset). For m > 1, the r-fractility of m is the number of equivalence classes of sequences NI(k/m) for 0 < k < m. Taking r = (1/1, 1/2, 1/3, 1/4, ... ) gives harmonic fractility.
In the case of harmonic fractility, r(n) = 1/n, we have n(j+1) = floor(L(j)/(x -Sum_{i=1..j} L(i-1)/(n(i)+1))) for j >= 0, L(0) = 1. - M. F. Hasler, Nov 05 2018

Examples

			Nested interval sequences NI(k/m) for m = 55:
The 5 equivalence classes are represented by
NI(1/55) = (55, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...),
NI(2/55) = (27, 2, 1, 1, 1, 1, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, ...),
NI(4/55) = (13, 4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1,...),
NI(6/55) = (9, 1, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, ...),
NI(22/55) = (2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, ...).
For example, NI(3/55) = (18, 1, 3, 1, 2, 1, 55, 1, 1, 1, ...) is equivalent to NI(1/55).
		

Crossrefs

Cf. A269804, A269805, A269806, A269807, A269809 (numbers with harmonic fractility 1, 2, ..., 6), A270000 (harmonic fractility of n).

Programs

Extensions

More terms from Jack W Grahl, Jun 27 2018
Edited by M. F. Hasler, Nov 05 2018

A269809 Numbers having harmonic fractility A270000(n) = 6.

Original entry on oeis.org

77, 95, 131, 145, 154, 190, 203, 209, 231, 247, 262, 275, 285, 290, 299, 308, 329, 377, 380, 393, 406, 418, 431, 435, 437, 443, 462, 494, 524, 529, 539, 545, 550, 559, 570, 580, 595, 598, 609, 616, 627, 658, 685, 689, 693, 705, 737, 741, 754, 760, 767, 786
Offset: 1

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Author

Keywords

Comments

In order to define (harmonic) fractility of an integer m > 1, we first define nested interval sequences. Suppose that r = (r(n)) is a sequence satisfying (i) 1 = r(1) > r(2) > r(3) > ... and (ii) r(n) -> 0. For x in (0,1], let n(1) be the index n such that r(n+1) < x <= r(n), and let L(1) = r(n(1)) - r(n(1)+1). Let n(2) be the largest index n such that x <= r(n(1)+1) + L(1)*r(n), and let L(2) = (r(n(2)) - r(n(2)+1))*L(1). Continue inductively to obtain the sequence (n(1), n(2), n(3), ...) =: NI(x), the r-nested interval sequence of x.
For fixed r, call x and y equivalent if NI(x) and NI(y) are eventually equal (up to an offset). For m > 1, the r-fractility of m is the number of equivalence classes of sequences NI(k/m) for 0 < k < m. Taking r = (1/1, 1/2, 1/3, 1/4, ... ) gives harmonic fractility.
In the case of harmonic fractility, r(n) = 1/n, we have n(j+1) = floor(L(j)/(x -Sum_{i=1..j} L(i-1)/(n(i)+1))) for j >= 0, L(0) = 1. - M. F. Hasler, Nov 05 2018

Examples

			Nested interval sequences NI(k/m) for m = 77:
The 6 equivalence classes are represented by
NI(1/77) = (77, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...),
NI(2/77) = (38, 2, 1, 1, 1, 1, 2, 3, 8, 2, 2, 1, 1, 1, 1, 2, 3, 8, 2, 2, 1, ...) (period length 9),
NI(3/77) = (25, 3, 1, 1, 1, 5, 15, 1, 5, 15, 1, 5, 15, 1, 5, 15, 1, 5, 15, ...),
NI(8/77) = (9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, 2, 9, ...),
NI(10/77) = (7, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, ...),
NI(14/77) = (5, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, ...).
For example, N(4/77) = (19, 1, 2, 1, 1, 1, 15, 1, 5, 15, 1, 5, ...) is equivalent to NI(3/77), and NI(6/77) = (12, 6, 1, 11, 1, 1, 1, ...) is equivalent to NI(1/77). - _M. F. Hasler_, Nov 05 2018
		

Crossrefs

Cf. A269804, A269805, A269806, A269807, A269808 (numbers with harmonic fractility 1, 2, 3, 4, 5, respectively); A270000 (harmonic fractility of n).

Programs

Extensions

More terms from Jack W Grahl, Jun 28 2018
Edited by M. F. Hasler, Nov 05 2018

A269982 Factorial fractility of n.

Original entry on oeis.org

1, 1, 2, 2, 1, 1, 2, 2, 3, 1, 2, 1, 2, 3, 2, 3, 2, 1, 4, 3, 2, 2, 2, 3, 2, 2, 4, 1, 3, 1, 2, 2, 4, 4, 3, 2, 2, 2, 4, 3, 3, 1, 3, 4, 4, 4, 2, 2, 4, 4, 3, 2, 2, 3, 4, 2, 2, 1, 4, 2, 3, 4, 2, 4, 2, 1, 5, 4, 5, 5, 3, 1, 3, 4, 3, 4, 2, 1, 4, 2, 4, 2, 4, 5, 2, 2
Offset: 2

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Author

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Comments

In order to define (factorial) fractility of an integer n > 1, we first define nested interval sequences. Suppose that r = (r(n)) is a sequence satisfying (i) 1 = r(1) > r(2) > r(3) > ... and (ii) r(n) -> 0. For x in (0,1], let n(1) be the index n such that r(n+1) < x <= r(n), and let L(1) = r(n(1))-r(n(1)+1). Let n(2) be the largest index n such that x <= r(n(1)+1) + L(1)*r(n), and let L(2) = (r(n(2)) - r(n(2)+1))*L(1). Continue inductively to obtain the sequence (n(1), n(2), n(3), ...) =: NI(x), the r-nested interval sequence of x.
For fixed r, call x and y equivalent if NI(x) and NI(y) are eventually equal (up to an offset). For n > 1, the r-fractility of n is the number of equivalence classes of sequences NI(m/n) for 0 < m < n. Taking r = (1/1, 1/2!, 1/3!, 1/4!, ... ) gives factorial fractility.
For factorial fractility, r(n) = 1/n!, n(j+1) = A084558(L(j)/(x - Sum_{i=1..j} L(i-1)/(n(i)+1)!)) for all j >= 0, L(0) = 1. - M. F. Hasler, Nov 05 2018

Examples

			NI(1/10) = (3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, ...)
NI(2/10) = (2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, ...)
NI(3/10) = (2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, ...)
NI(4/10) = (2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, ...)
NI(5/10) = (2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...)
NI(6/10) = (1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, ...)
NI(7/10) = (1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, ...)
NI(8/10) = (1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, ...)
NI(9/10) = (1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, ...),
so that there are 3 equivalence classes for n = 10, and the factorial fractility of 10 is 3.
		

Crossrefs

Cf. A000142 (factorial numbers), A084558 (largest m: m! < n).
Cf. A269983, A269984, A269985, A269986, A269987, A269988: numbers with factorial fractility k = 1, 2, ..., 6, respectively.
Cf. A269570 (binary fractility), A270000 (harmonic fractility).

Programs

  • Mathematica
    A269982[n_] := CountDistinct[With[{l = NestWhileList[Rescale[#, {1/(Floor[x] + 1)!, 1/Floor[x]!} /. FindRoot[1/x! == #, {x, 1}]] &, #, UnsameQ, All]}, Min@l[[First@First@Position[l, Last@l] ;;]]] & /@ Range[1/n, 1 - 1/n, 1/n]] (* Davin Park, Nov 19 2016 *)
  • PARI
    A269982(n)=#Set(vector(n-1, k, NIFR(k/n))) \\ where:
    NIFR(x, n, L=1, S=[], c=0)={for(i=2, oo, n=A084558(L\x); S=setunion(S, [x/L]); x-=L/(n+1)!; L/=(n+1)!\n; setsearch(S, x/L)&& if(c, break, c=!S=[])); S[1]} \\ variant of the function NIF() below; returns just a unique representative (smallest x/L occurring within the period) of the equivalence class.
    NIF(x, n=[], L=1, S=[], c=0)={for(i=2, oo, n=concat(n, A084558(L\x)); c|| S=setunion(S, [x/L]); x-=L/(n[#n]+1)!; L/=(n[#n]-1)!*(n[#n]+1); if(!c, setsearch(S, x/L)&& [c, S]=[i, x/L], x/L==S, c-=i; break)); [n[1..2*c-1], n[c..-1]]} \\ Returns [transition, period] of "factorial" NI(x). (End)

Extensions

Edited by M. F. Hasler, Nov 05 2018

A269984 Numbers k having factorial fractility A269982(k) = 2.

Original entry on oeis.org

4, 5, 8, 9, 12, 14, 16, 18, 22, 23, 24, 26, 27, 32, 33, 37, 38, 39, 48, 49, 53, 54, 57, 58, 61, 64, 66, 78, 81, 83, 86, 87, 96, 97, 101, 107, 113, 114, 121, 129, 131, 139, 163, 169, 174, 178, 181, 193, 218, 227, 241, 257, 263, 267, 277, 302, 317, 327, 331
Offset: 1

Views

Author

Keywords

Comments

See A269982 for a definition of factorial fractility and a guide to related sequences.

Examples

			NI(1/5) = (2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, ...)
NI(2/5) = (2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, ...)
NI(3/5) = (1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, ...)
NI(4/5) = (1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, ...)
so there are 2 equivalences classes for n = 5, and the fractility of 5 is 2.
		

Crossrefs

Cf. A000142 (factorial numbers), A269982 (factorial fractility of n); A269983, A269985, A269986, A269987, A269988 (numbers with factorial fractility 1, 3, ..., 6, respectively).
Cf. A269570 (binary fractility), A270000 (harmonic fractility).

Programs

  • Mathematica
    A269982[n_] := CountDistinct[With[{l = NestWhileList[
             Rescale[#, {1/(Floor[x] + 1)!, 1/Floor[x]!} /.
                FindRoot[1/x! == #, {x, 1}]] &, #, UnsameQ, All]},
          Min@l[[First@First@Position[l, Last@l] ;;]]] & /@
        Range[1/n, 1 - 1/n, 1/n]]; (* Davin Park, Nov 19 2016 *)
    Select[Range[2, 500], A269982[#] == 2 &] (* Robert Price, Sep 19 2019 *)
  • PARI
    select( is_A269984(n)=A269982(n)==2, [1..300]) \\ M. F. Hasler, Nov 05 2018

Extensions

Edited by M. F. Hasler, Nov 05 2018

A269985 Numbers k having factorial fractility A269982(k) = 3.

Original entry on oeis.org

10, 15, 17, 21, 25, 30, 36, 41, 42, 44, 52, 55, 62, 72, 74, 76, 88, 93, 98, 99, 103, 104, 106, 108, 111, 118, 122, 125, 128, 132, 134, 137, 146, 149, 155, 158, 162, 166, 173, 176, 177, 179, 183, 186, 192, 198, 201, 202, 203, 214, 219, 226, 228, 237, 242, 249
Offset: 1

Views

Author

Keywords

Comments

See A269982 for a definition of factorial fractility and a guide to related sequences.

Examples

			NI(1/10) = (3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, ...),
NI(2/10) = (2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, ...) ~ NI(1/10),
NI(3/10) = (2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, ...),
NI(4/10) = (2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, ...) ~ NI(3/10),
NI(5/10) = (2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...),
NI(6/10) = (1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, ...) ~ NI(1/10),
NI(7/10) = (1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, ...) ~ NI(3/10),
NI(8/10) = (1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, ...) ~ NI(1/10),
NI(9/10) = (1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, ...) ~ NI(1/10),
so that there are 3 equivalence classes for n = 10, so the factorial fractility of 10 is 3.
		

Crossrefs

Cf. A000142 (factorial numbers), A269982 (factorial fractility of n); A269983, A269984, A269986, A269987, A269988 (numbers with factorial fractility 1, 2, ..., 6, respectively).
Cf. A269570 (binary fractility), A270000 (harmonic fractility).

Programs

  • Mathematica
    A269982[n_] := CountDistinct[With[{l = NestWhileList[
            Rescale[#, {1/(Floor[x] + 1)!, 1/Floor[x]!} /.
               FindRoot[1/x! == #, {x, 1}]] &, #, UnsameQ, All]},
         Min@l[[First@First@Position[l, Last@l] ;;]]] & /@
       Range[1/n, 1 - 1/n, 1/n]]; (* Davin Park, Nov 19 2016 *)
    Select[Range[2, 500], A269982[#] == 3 &] (* Robert Price, Sep 19 2019 *)
  • PARI
    select( is_A269985(n)=A269982(n)==2, [1..200]) \\ M. F. Hasler, Nov 05 2018

Extensions

Edited by M. F. Hasler, Nov 05 2018

A269986 Numbers k having factorial fractility A269982(k) = 4.

Original entry on oeis.org

20, 28, 34, 35, 40, 45, 46, 47, 50, 51, 56, 60, 63, 65, 69, 75, 77, 80, 82, 84, 90, 91, 102, 110, 112, 116, 117, 120, 123, 124, 133, 135, 144, 147, 148, 150, 152, 156, 159, 160, 165, 167, 171, 172, 194, 206, 208, 209, 216, 217, 222, 223, 234, 236, 239, 240
Offset: 1

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Comments

See A269982 for a definition of factorial fractility and a guide to related sequences.

Examples

			NI(1/20) = (3, 3, 2, 3, 2, 1, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 2, ...)
NI(5/20) = (2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, ...)
NI(6/20) = (2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, ...)
NI(10/20) = (2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...).
These 4 equivalence classes represent all the classes for n = 20, so the factorial fractility of 20 is 4.
		

Crossrefs

Cf. A000142 (factorial numbers), A269982 (factorial fractility of n); A269983, A269984, A269985, A269987, A269988 (numbers with factorial fractility 1, 2, ..., 6, respectively).
Cf. A269570 (binary fractility), A270000 (harmonic fractility).

Programs

  • Mathematica
    A269982[n_] := CountDistinct[With[{l = NestWhileList[
            Rescale[#, {1/(Floor[x] + 1)!, 1/Floor[x]!} /.
               FindRoot[1/x! == #, {x, 1}]] &, #, UnsameQ, All]},
         Min@l[[First@First@Position[l, Last@l] ;;]]] & /@
       Range[1/n, 1 - 1/n, 1/n]]; (* Davin Park, Nov 19 2016 *)
    Select[Range[2, 500], A269982[#] == 4 &] (* Robert Price, Sep 19 2019 *)
  • PARI
    select( is_A269986(n)=A269982(n)==4, [1..200]) \\ M. F. Hasler, Nov 05 2018

Extensions

Edited by M. F. Hasler, Nov 05 2018
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