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 16 results. Next

A213859 a(n) = 2^n mod (n+2).

Original entry on oeis.org

1, 2, 0, 3, 4, 4, 0, 2, 6, 6, 4, 7, 8, 2, 0, 9, 16, 10, 4, 2, 12, 12, 16, 8, 14, 20, 4, 15, 16, 16, 0, 2, 18, 22, 16, 19, 20, 2, 24, 21, 16, 22, 4, 38, 24, 24, 16, 32, 6, 2, 4, 27, 34, 52, 8, 2, 30, 30, 4, 31, 32, 2, 0, 8, 16, 34, 4, 2, 46, 36, 16, 37, 38, 17
Offset: 0

Views

Author

Alex Ratushnyak, Jun 22 2012

Keywords

Comments

Conjectures:
1. Indices of zeros: 2^(x+2)-2, x >= 0.
2. There are infinitely many n's such that a(n)=n.
3. Every integer k >= 0 appears in a(n) at least once.
4. Every k >= 0 appears in a(n) infinitely many times.

Crossrefs

Programs

  • Magma
    [Modexp(2,n,n+2): n in [0..120]]; // G. C. Greubel, Jan 11 2023
    
  • Mathematica
    Table[PowerMod[2, n, n+2], {n, 0, 100}] (* T. D. Noe, Jun 26 2012 *)
  • Python
    print([2**n % (n+2) for n in range(222)])
    
  • SageMath
    [power_mod(2,n,n+2) for n in range(121)] # G. C. Greubel, Jan 11 2023

Formula

a(n) = 2^n mod (n+2).
a(n) = A106262(2*n, n). - G. C. Greubel, Jan 11 2023

A066607 a(n) = 3^n mod n^3.

Original entry on oeis.org

0, 1, 0, 17, 118, 81, 129, 417, 0, 49, 124, 945, 1498, 177, 1782, 1857, 1958, 729, 3917, 401, 7398, 8721, 6466, 4833, 68, 14049, 0, 3889, 9718, 26649, 24648, 16001, 3294, 6537, 32457, 41553, 34857, 33601, 26703, 32801, 9310, 62721, 76070, 50417, 12393
Offset: 1

Views

Author

Amarnath Murthy, Dec 22 2001

Keywords

Examples

			a(7) = 129 as 3^7 = 2187 = (7^3)*6 + 129.
		

Crossrefs

Cf. A066606.

Programs

  • Mathematica
    Table[ Mod[ 3^n, n^3], {n, 1, 50} ]
  • PARI
    a(n) = { lift(Mod(3, n^3)^n) } \\ Harry J. Smith, Mar 10 2010
  • Sage
    [power_mod(3,n,n^3)for n in range(1,46)] # Zerinvary Lajos, Nov 28 2009
    

Extensions

More terms from Floor van Lamoen and Robert G. Wilson v, Dec 23 2001

A233442 a(n) = 2^n mod n^3.

Original entry on oeis.org

0, 4, 8, 16, 32, 64, 128, 256, 512, 24, 717, 640, 1601, 2664, 2393, 0, 3334, 5536, 3004, 576, 4166, 9640, 5545, 8704, 7557, 3696, 19034, 6400, 20244, 5824, 29204, 0, 21293, 12176, 13493, 40960, 41146, 25008, 16154, 11776, 55680, 56008, 20642, 79040, 14957, 1016
Offset: 1

Views

Author

Alex Ratushnyak, Dec 09 2013

Keywords

Crossrefs

Programs

  • Mathematica
    Array[PowerMod[2, #, #^3] &, 50] (* Paolo Xausa, Mar 27 2025 *)
  • Python
    for n in range(1,100):  print(2**n % n**3, end=', ')

Formula

a(n) = A000079(n) mod A000578(n).

A233471 a(n) = 3^n mod n^2.

Original entry on oeis.org

0, 1, 0, 1, 18, 9, 31, 33, 0, 49, 3, 81, 146, 177, 207, 65, 224, 81, 307, 1, 342, 9, 118, 225, 68, 529, 0, 753, 467, 549, 623, 641, 27, 757, 607, 81, 632, 389, 846, 801, 905, 981, 261, 81, 243, 1757, 1554, 2241, 2383, 249, 792, 1329, 851, 729, 1332, 2529, 1737, 2793, 298
Offset: 1

Views

Author

Alex Ratushnyak, Dec 11 2013

Keywords

Examples

			a(4) = 1 because 3^4 = 81, 4^2 = 16 and 81 = 1 mod 80.
a(5) = 18 because 3^5 = 243, 5^2 = 25 and 243 = 18 mod 25.
		

Crossrefs

Programs

  • Maple
    a:= n-> 3&^n mod n^2:
    seq(a(n), n=1..60);  # Alois P. Heinz, Dec 22 2013
  • Mathematica
    Table[Mod[3^n, n^2], {n, 100}] (* Alonso del Arte, Dec 11 2013 *)
    Table[PowerMod[3,n,n^2],{n,100}] (* Harvey P. Dale, Aug 27 2019 *)
  • PARI
    a(n) = lift(Mod(3, n^2)^n); \\ Michel Marcus, May 05 2021
  • Python
    for n in range(1,100):  print(str(3**n % n**2), end=',')
    

Formula

a(n) = A000244(n) mod A000290(n).

A289382 a(n) = 2^n mod triangular(n).

Original entry on oeis.org

0, 1, 2, 6, 2, 1, 16, 4, 17, 34, 2, 40, 2, 4, 8, 120, 104, 1, 78, 46, 134, 70, 140, 16, 132, 121, 134, 30, 2, 94, 64, 400, 206, 429, 158, 334, 2, 4, 8, 616, 494, 1, 690, 346, 692, 142, 848, 64, 912, 1024, 8, 796, 797, 379, 1528, 4, 350, 178, 1418, 916, 2, 4, 512, 1056, 32, 2011
Offset: 1

Views

Author

Alex Ratushnyak, Jul 04 2017

Keywords

Examples

			a(6) = 2**6 mod (6*7/2) = 64 mod 21 = 1.
		

Crossrefs

Programs

  • Maple
    seq(2^n mod n*(n+1)/2, n=1..100); # Robert Israel, Jul 04 2017
  • Mathematica
    Table[Mod[2^n, n (n + 1)/2], {n, 66}] (* Michael De Vlieger, Jul 04 2017 *)
    PowerMod[2,#,(#(#+1))/2]&/@Range[70] (* Harvey P. Dale, Oct 12 2018 *)
  • PARI
    a(n) = lift(Mod(2, n*(n+1)/2)^n); \\ Michel Marcus, Jul 04 2017
  • Python
    for n in range(1,99): print(str(int(2**n % (n*(n+1)/2))), end=', ')
    

Formula

a(n) = A000079(n) mod A000217(n) = 2^n mod n*(n+1)/2.
a(n) = 1 for n>1 in A272934. - Michel Marcus, Jul 04 2017

A066429 a(n) = 7^n mod n^7.

Original entry on oeis.org

0, 49, 343, 2401, 16807, 117649, 0, 1570497, 2089855, 2475249, 9122472, 10209313, 5300159, 98001617, 62916193, 84245889, 82474028, 145795249, 530403874, 57612001, 1611673651, 2006506001, 832663280, 2652148801, 4541072682, 7457168625, 3383428402, 6778582433, 4637847366
Offset: 1

Views

Author

Robert G. Wilson v, Dec 27 2001

Keywords

Crossrefs

Cf. A066606.

Programs

  • Mathematica
    Table[ Mod[ 7^n, n^7], {n, 1, 30} ]
    Table[PowerMod[7,n,n^7],{n,30}] (* Harvey P. Dale, Dec 25 2023 *)
  • PARI
    a(n) = { lift(Mod(7, n^7)^n) } \\ Harry J. Smith, Feb 13 2010

A066430 a(n) = 8^n mod n^8.

Original entry on oeis.org

0, 64, 512, 4096, 32768, 262144, 2097152, 0, 5077565, 73741824, 15579352, 352387072, 769038655, 195124224, 1009588832, 0, 4384458125, 2836131328, 9009163584, 7006846976, 33653509289, 41376995328, 17808619293, 26138902528, 11605068943, 200037316608, 161669290688
Offset: 1

Views

Author

Robert G. Wilson v, Dec 27 2001

Keywords

Crossrefs

Cf. A066606.

Programs

  • Mathematica
    Table[ Mod[ 8^n, n^8], {n, 1, 30} ]
  • PARI
    a(n) = { lift(Mod(8, n^8)^n) } \\ Harry J. Smith, Feb 13 2010
  • Sage
    [power_mod(8,n,n^8)for n in range(1,24)] # Zerinvary Lajos, Nov 28 2009
    

A066431 a(n) = 9^n mod n^9.

Original entry on oeis.org

0, 81, 729, 6561, 59049, 531441, 4782969, 43046721, 0, 486784401, 727739626, 3801397473, 7390478182, 5013665073, 26942641524, 68218142337, 50040016962, 127461340881, 20157955560, 179056928801, 95734214766, 798384194161, 812529625653, 123794634177, 1880664942124
Offset: 1

Views

Author

Robert G. Wilson v, Dec 27 2001

Keywords

Crossrefs

Cf. A066606.

Programs

  • Mathematica
    Table[ Mod[ 9^n, n^9], {n, 1, 30} ]
    Table[PowerMod[9,n,n^9],{n,30}] (* Harvey P. Dale, May 30 2022 *)
  • PARI
    a(n) = { lift(Mod(9, n^9)^n) } \\ Harry J. Smith, Feb 13 2010

A066432 a(n) = 10^n mod n^10.

Original entry on oeis.org

0, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000, 0, 22187726197, 9322172416, 74188586872, 207144033280, 88222656250, 1041257005056, 654556028253, 1391503283200, 4084075030363, 0, 2770357806334, 15498434643968, 29882775483895, 5484153143296
Offset: 1

Views

Author

Robert G. Wilson v, Dec 27 2001

Keywords

Crossrefs

Cf. A066606.

Programs

  • Mathematica
    Table[ Mod[ 10^n, n^10], {n, 1, 25} ]
  • PARI
    a(n) = { lift(Mod(10, n^10)^n) } \\ Harry J. Smith, Feb 13 2010

A066444 a(n) = 11^n mod n^11.

Original entry on oeis.org

0, 121, 1331, 14641, 161051, 1771561, 19487171, 214358881, 2357947691, 25937424601, 0, 166394893969, 471664657228, 3140272804489, 8065845196901, 16532101601985, 5101754322287, 57157537871161, 73663224996225, 17332560009201, 240252754633991, 96720656337129, 29113945750083
Offset: 1

Views

Author

Robert G. Wilson v, Dec 27 2001

Keywords

Crossrefs

Cf. A066606.

Programs

  • Mathematica
    Table[ Mod[11^n, n^11], {n, 1, 20} ]
  • PARI
    a(n) = { lift(Mod(11, n^11)^n) } \\ Harry J. Smith, Feb 14 2010
Showing 1-10 of 16 results. Next