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.

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A250176 Numbers n such that Phi_20(n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

4, 9, 11, 16, 19, 26, 34, 45, 54, 70, 86, 91, 96, 101, 105, 109, 110, 119, 120, 126, 129, 139, 141, 149, 171, 181, 190, 195, 215, 229, 260, 276, 299, 305, 309, 311, 314, 319, 334, 339, 369, 375, 414, 420, 425, 444, 470, 479, 485, 506, 519, 534, 540, 550
Offset: 1

Views

Author

Eric Chen, Dec 24 2014

Keywords

Crossrefs

Cf. A008864 (1), A006093 (2), A002384 (3), A005574 (4), A049409 (5), A055494(6), A100330 (7), A000068 (8), A153439 (9), A246392 (10), A162862(11), A246397 (12), A217070 (13), A006314 (16), A217071 (17), A164989(18), A217072 (19), A217073 (23), A153440 (27), A217074 (29), A217075(31), A006313 (32), A097475 (36), A217076 (37), A217077 (41), A217078(43), A217079 (47), A217080 (53), A217081 (59), A217082 (61), A006315(64), A217083 (67), A217084 (71), A217085 (73), A217086 (79), A153441(81), A217087 (83), A217088 (89), A217089 (97), A006316 (128), A153442(243), A056994 (256), A056995 (512), A057465 (1024), A057002 (2048), A088361 (4096), A088362 (8192), A226528 (16384), A226529 (32768), A226530(65536).

Programs

  • Mathematica
    Select[Range[600], PrimeQ[Cyclotomic[20, #]] &] (* Vincenzo Librandi, Jan 16 2015 *)
  • PARI
    isok(n) = isprime(polcyclo(20, n)); \\ Michel Marcus, Sep 29 2015

Extensions

More terms from Vincenzo Librandi, Jan 16 2015

A253240 Square array read by antidiagonals: T(m, n) = Phi_m(n), the m-th cyclotomic polynomial at x=n.

Original entry on oeis.org

1, 1, -1, 1, 0, 1, 1, 1, 2, 1, 1, 2, 3, 3, 1, 1, 3, 4, 7, 2, 1, 1, 4, 5, 13, 5, 5, 1, 1, 5, 6, 21, 10, 31, 1, 1, 1, 6, 7, 31, 17, 121, 3, 7, 1, 1, 7, 8, 43, 26, 341, 7, 127, 2, 1, 1, 8, 9, 57, 37, 781, 13, 1093, 17, 3, 1, 1, 9, 10, 73, 50, 1555, 21, 5461, 82, 73, 1, 1, 1, 10, 11, 91, 65, 2801, 31, 19531, 257, 757, 11, 11, 1, 1, 11, 12, 111, 82, 4681, 43, 55987, 626, 4161, 61, 2047, 1, 1
Offset: 0

Views

Author

Eric Chen, Apr 22 2015

Keywords

Comments

Outside of rows 0, 1, 2 and columns 0, 1, only terms of A206942 occur.
Conjecture: There are infinitely many primes in every row (except row 0) and every column (except column 0), the indices of the first prime in n-th row and n-th column are listed in A117544 and A117545. (See A206864 for all the primes apart from row 0, 1, 2 and column 0, 1.)
Another conjecture: Except row 0, 1, 2 and column 0, 1, the only perfect powers in this table are 121 (=Phi_5(3)) and 343 (=Phi_3(18)=Phi_6(19)).

Examples

			Read by antidiagonals:
m\n  0   1   2   3   4   5   6   7   8   9  10  11  12
------------------------------------------------------
0    1   1   1   1   1   1   1   1   1   1   1   1   1
1   -1   0   1   2   3   4   5   6   7   8   9  10  11
2    1   2   3   4   5   6   7   8   9  10  11  12  13
3    1   3   7  13  21  31  43  57  73  91 111 133 157
4    1   2   5  10  17  26  37  50  65  82 101 122 145
5    1   5  31 121 341 781 ... ... ... ... ... ... ...
6    1   1   3   7  13  21  31  43  57  73  91 111 133
etc.
The cyclotomic polynomials are:
n        n-th cyclotomic polynomial
0        1
1        x-1
2        x+1
3        x^2+x+1
4        x^2+1
5        x^4+x^3+x^2+x+1
6        x^2-x+1
...
		

Crossrefs

Main diagonal is A070518.
Indices of primes in n-th column for n = 1-10 are A246655, A072226, A138933, A138934, A138935, A138936, A138937, A138938, A138939, A138940.
Indices of primes in main diagonal is A070519.
Cf. A117544 (indices of first prime in n-th row), A085398 (indices of first prime in n-th row apart from column 1), A117545 (indices of first prime in n-th column).
Cf. A206942 (all terms (sorted) for rows>2 and columns>1).
Cf. A206864 (all primes (sorted) for rows>2 and columns>1).

Programs

  • Mathematica
    Table[Cyclotomic[m, k-m], {k, 0, 49}, {m, 0, k}]
  • PARI
    t1(n)=n-binomial(floor(1/2+sqrt(2+2*n)), 2)
    t2(n)=binomial(floor(3/2+sqrt(2+2*n)), 2)-(n+1)
    T(m, n) = if(m==0, 1, polcyclo(m, n))
    a(n) = T(t1(n), t2(n))

Formula

T(m, n) = Phi_m(n)

A259257 Primes of the form n^4 - n^3 + n^2 - n + 1.

Original entry on oeis.org

11, 61, 521, 9091, 13421, 19141, 61681, 152381, 185641, 224071, 1151041, 1824841, 2031671, 3341101, 4778021, 5200081, 8987221, 25058741, 31224301, 32928901, 40454321, 42521761, 150451621, 212601841, 250062751, 292268861, 310565641, 329708341, 339604921
Offset: 1

Views

Author

Robert Price, Jun 22 2015

Keywords

Crossrefs

Programs

  • Magma
    [a: n in [0..200] | IsPrime(a) where a is n^4-n^3+n^2-n+1]; // Vincenzo Librandi, Jun 23 2015
    
  • Mathematica
    Select[Table[Cyclotomic[10, n], {n, 0, 200}], PrimeQ]
    Select[Table[n^4 - n^3 + n^2 - n + 1, {n, 200}], PrimeQ] (* Vincenzo Librandi, Jun 23 2015 *)
  • PARI
    lista(nn) = for (n=1, nn, if (isprime(p=polcyclo(10, n)), print1(p, ", "))); \\ Michel Marcus, Jun 23 2015

Formula

a(n) = A246392(A060884(n)).

A250182 Numbers n such that Phi_28(n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

4, 5, 7, 13, 25, 33, 41, 63, 74, 80, 88, 94, 96, 104, 116, 144, 149, 151, 154, 165, 167, 174, 183, 191, 197, 208, 231, 241, 262, 268, 270, 290, 318, 319, 361, 368, 376, 390, 394, 412, 431, 434, 442, 464, 489, 492, 521, 529, 556, 568, 574, 575, 585, 589, 613, 629, 639, 654, 666, 667, 672, 683, 684
Offset: 1

Views

Author

R. J. Mathar, Jan 09 2015

Keywords

Crossrefs

Cf. A246392.

Programs

  • Mathematica
    Select[Range[700], PrimeQ[Cyclotomic[28, #]] &] (* Vincenzo Librandi, Jan 17 2015 *)
  • PARI
    isok(n) = isprime(polcyclo(28, n)); \\ Michel Marcus, Jan 17 2015

A250183 Numbers n such that Phi(30,n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

2, 6, 7, 8, 9, 16, 18, 20, 26, 29, 31, 32, 33, 40, 41, 47, 57, 76, 82, 87, 88, 93, 101, 109, 120, 121, 125, 133, 140, 144, 162, 163, 175, 178, 183, 186, 191, 196, 215, 216, 218, 227, 233, 242, 253, 266, 267, 273, 276, 278, 304, 312, 317, 319, 328, 336, 374, 380
Offset: 1

Views

Author

R. J. Mathar, Jan 12 2015

Keywords

Crossrefs

Cf. A246392.

Programs

  • Mathematica
    Select[Range[400], PrimeQ[Cyclotomic[30, #]] &] (* Vincenzo Librandi, Jan 17 2015 *)
  • PARI
    isok(n) = isprime(polcyclo(30, n)); \\ Michel Marcus, Jan 17 2015

A250184 Numbers n such that Phi(33,n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

2, 3, 13, 14, 18, 31, 44, 59, 62, 75, 80, 104, 109, 145, 185, 213, 273, 282, 309, 321, 337, 379, 399, 405, 411, 430, 452, 464, 470, 522, 535, 560, 566, 586, 593, 597, 653, 654, 688, 702, 704, 727, 728, 744, 746, 780, 805, 806, 816, 822, 829, 846, 856
Offset: 1

Views

Author

R. J. Mathar, Jan 12 2015

Keywords

Crossrefs

Cf. A246392.

Programs

  • Mathematica
    Select[Range[900], PrimeQ[Cyclotomic[33, #]] &] (* Vincenzo Librandi, Jan 17 2015 *)
  • PARI
    isok(n) = isprime(polcyclo(30, n)); \\ Michel Marcus, Jan 17 2015

A250186 Numbers n such that Phi(35,n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

14, 33, 39, 55, 112, 130, 132, 138, 168, 176, 179, 186, 189, 195, 210, 246, 259, 264, 310, 318, 346, 417, 431, 467, 478, 480, 534, 545, 564, 567, 661, 671, 741, 744, 749, 757, 786, 794, 804, 825, 851, 866, 911, 948, 955, 962, 976, 992, 1014, 1033, 1042, 1082, 1109, 1161, 1193, 1220, 1244, 1260, 1268, 1278, 1313, 1414, 1437
Offset: 1

Views

Author

R. J. Mathar, Jan 12 2015

Keywords

Crossrefs

Cf. A246392.

Programs

  • Mathematica
    Select[Range[1500], PrimeQ[Cyclotomic[35, #]] &] (* Vincenzo Librandi, Jan 16 2015 *)
  • PARI
    {is(n)=isprime(polcyclo(35,n))};
    for(n=1,1000, if(is(n), print1(n, ", "))) \\ G. C. Greubel, May 20 2018

A250188 Numbers n such that Phi(39,n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

10, 23, 86, 240, 254, 284, 340, 369, 371, 378, 382, 407, 422, 448, 459, 574, 582, 613, 619, 667, 686, 703, 767, 769, 844, 851, 875, 881, 944, 987, 995, 1207, 1219, 1233, 1279, 1292, 1343, 1372, 1399, 1409, 1445, 1468, 1497, 1500, 1557, 1586, 1598, 1633, 1645, 1677, 1760, 1807, 1835
Offset: 1

Views

Author

R. J. Mathar, Jan 12 2015

Keywords

Crossrefs

Cf. A246392.

Programs

  • Mathematica
    Select[Range[1900], PrimeQ[Cyclotomic[39, #]] &] (* Vincenzo Librandi, Jan 16 2015 *)
  • PARI
    {is(n)=isprime(polcyclo(39,n))};
    for(n=1,1000, if(is(n), print1(n, ", "))) \\ G. C. Greubel, May 20 2018

A250189 Numbers n such that Phi(40,n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

2, 3, 4, 31, 37, 39, 46, 77, 98, 119, 124, 143, 144, 154, 169, 197, 205, 232, 245, 266, 291, 295, 297, 305, 308, 319, 332, 333, 413, 426, 431, 437, 454, 459, 472, 483, 513, 528, 531, 542, 579, 617, 619, 635, 647, 677, 724, 737, 748, 780, 806, 815, 819, 820, 840, 851, 858, 870, 875, 907, 920, 927, 940, 983, 1002, 1028
Offset: 1

Views

Author

R. J. Mathar, Jan 12 2015

Keywords

Crossrefs

Cf. A246392.

Programs

  • Mathematica
    Select[Range[1200], PrimeQ[Cyclotomic[40, #]] &] (* Vincenzo Librandi, Jan 16 2015 *)
  • PARI
    {is(n)=isprime(polcyclo(40,n))};
    for(n=1,1000, if(is(n), print1(n, ", "))) \\ G. C. Greubel, May 20 2018

A250190 Numbers n such that Phi(42,n) is prime, where Phi is the cyclotomic polynomial.

Original entry on oeis.org

2, 6, 8, 11, 23, 35, 41, 49, 58, 65, 85, 88, 97, 107, 111, 139, 144, 161, 170, 197, 214, 217, 223, 230, 238, 247, 274, 298, 301, 323, 382, 389, 393, 398, 403, 427, 445, 452, 473, 480, 497, 511, 561, 575, 595, 601, 604, 606, 615, 629, 651, 652, 680, 685, 702, 725, 762, 770, 774, 781, 805, 814, 912, 918, 942, 987, 1030
Offset: 1

Views

Author

R. J. Mathar, Jan 12 2015

Keywords

Crossrefs

Cf. A246392.

Programs

  • Mathematica
    Select[Range[1100], PrimeQ[Cyclotomic[42, #]] &] (* Vincenzo Librandi, Jan 16 2015 *)
  • PARI
    {is(n)=isprime(polcyclo(42,n))};
    for(n=1,1000, if(is(n)==1, print1(n, ", "))) \\ G. C. Greubel, May 18 2018
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