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 14 results. Next

A056579 1+2n+3n^2+4n^3+5n^4.

Original entry on oeis.org

1, 15, 129, 547, 1593, 3711, 7465, 13539, 22737, 35983, 54321, 78915, 111049, 152127, 203673, 267331, 344865, 438159, 549217, 680163, 833241, 1010815, 1215369, 1449507, 1715953, 2017551, 2357265, 2738179, 3163497, 3636543
Offset: 0

Views

Author

Henry Bottomley, Jun 29 2000

Keywords

Examples

			For n>5 this is 54321 translated from base n to base 10
		

Crossrefs

Note: 1+2x+3x^2+4x^3+5x^4 is derivative of 1+x+x^2+x^3+x^4 +x^5, i.e. A053700. Cf. A000012, A005408, A056109, A056578.

Programs

  • Mathematica
    Join[{1},Table[Total[Table[i n^(i-1),{i,5}]],{n,30}]] (* or *) LinearRecurrence[{5,-10,10,-5,1},{1,15,129,547,1593},30] (* Harvey P. Dale, Sep 20 2017 *)
  • PARI
    a(n)=1+2*n+3*n^2+4*n^3+5*n^4 \\ Charles R Greathouse IV, Oct 07 2015

Formula

a(n) =(A053700(n+1)-A053700(n-1))/2-10n^2-4n-2.
G.f.: -(3*x^4+42*x^3+64*x^2+10*x+1) / (x-1)^5. - Colin Barker, May 04 2013

A123059 Primes of the form 1 + 2*k + 3*k^2 + 4*k^3.

Original entry on oeis.org

313, 7369, 11593, 24337, 44089, 57073, 90217, 160753, 570649, 964969, 1060993, 1916617, 3349033, 4532113, 5360521, 6614137, 7308289, 9252409, 11035081, 12006433, 14680513, 15852457, 16461121, 22654417, 29318833, 34083913, 39339193, 41583937, 42737641, 51416353
Offset: 1

Views

Author

Zak Seidov, Sep 26 2006

Keywords

Comments

Corresponding values of k are in A123076.

Crossrefs

Programs

  • Magma
    [ a: n in [0..300] | IsPrime(a) where a is 1+2*n+3*n^2+4*n^3 ]; // Vincenzo Librandi, Dec 17 2010
  • Mathematica
    Select[Total/@Table[(Range[4]n^Range[0,3]),{n,250}],PrimeQ]  (* Harvey P. Dale, Jan 18 2011 *)

Formula

a(n) = A056578(A123076(n)). - Elmo R. Oliveira, Apr 20 2025

A059045 Square array T(n,k) read by antidiagonals where T(0,k) = 0 and T(n,k) = 1 + 2k + 3k^2 + ... + n*k^(n-1).

Original entry on oeis.org

0, 1, 0, 1, 1, 0, 1, 3, 1, 0, 1, 6, 5, 1, 0, 1, 10, 17, 7, 1, 0, 1, 15, 49, 34, 9, 1, 0, 1, 21, 129, 142, 57, 11, 1, 0, 1, 28, 321, 547, 313, 86, 13, 1, 0, 1, 36, 769, 2005, 1593, 586, 121, 15, 1, 0, 1, 45, 1793, 7108, 7737, 3711, 985, 162, 17, 1, 0, 1, 55, 4097, 24604, 36409
Offset: 0

Views

Author

Henry Bottomley, Dec 18 2000

Keywords

Examples

			   0,   0,   0,    0,     0,      0,      0,      0,       0, ...
   1,   1,   1,    1,     1,      1,      1,      1,       1, ...
   1,   3,   5,    7,     9,     11,     13,     15,      17, ...
   1,   6,  17,   34,    57,     86,    121,    162,     209, ...
   1,  10,  49,  142,   313,    586,    985,   1534,    2257, ...
   1,  15, 129,  547,  1593,   3711,   7465,  13539,   22737, ...
   1,  21, 321, 2005,  7737,  22461,  54121, 114381,  219345, ...
   1,  28, 769, 7108, 36409, 131836, 380713, 937924, 2054353, ...
		

Crossrefs

Programs

  • Maple
    A059045 := proc(n,k)
        if k = 1 then
            n*(n+1) /2 ;
        else
            (1+n*k^(n+1)-k^n*(n+1))/(k-1)^2 ;
        end if;
    end proc: # R. J. Mathar, Mar 29 2013

Formula

T(n,k) = n*k^(n-1)+T(n-1, k) = (n*k^(n+1)-(n+1)*k^n+1)/(k-1)^2.

A113630 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6 + 8*n^7 + 9*n^8.

Original entry on oeis.org

1, 45, 4097, 83653, 757305, 4272461, 17736745, 59409477, 169826513, 429794605, 987654321, 2098573445, 4178995657, 7879732173, 14181546905, 24517448581, 40926266145, 66242446637, 104327377633, 160347899205, 241108033241
Offset: 0

Views

Author

Jonathan Vos Post, Jan 14 2006

Keywords

Comments

1 + 2x + 3x^2 + 4x^3 + 5x^4 + 6x^5 + 7*x^6 + 8*x^7 + 9*x^8 is the derivative of 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + x^7 + x^8 + x^9 = (x^10 - 1)/(x-1).

Examples

			a(3) = 1 + 2*3 + 3*3^2 + 4*3^3 + 5*3^4 + 6*3^5 + 7*3^6 + 8*3^7 + 9*3^8 = 83653 is prime.
a(5) = 1 + 2*5 + 3*5^2 + 4*5^3 + 5*5^4 + 6*5^5 + 7*5^6 + 8*5^7 + 9*5^8 = 4272461 is prime.
a(8) = 1 + 2*8 + 3*8^2 + 4*8^3 + 5*8^4 + 6*8^5 + 7*8^6 + 8*8^7 + 9*8^8 = 169826513 is prime.
a(23) = 1 + 2*23 + 3*23^2 + 4*23^3 + 5*23^4 + 6*23^5 + 7*23^6 + 8*23^7 + 9*23^8 = 733113789893 is prime.
		

Crossrefs

Programs

  • Haskell
    a113630 n = sum $ zipWith (*) [1..9] $ iterate (* n) 1
    -- Reinhard Zumkeller, Nov 22 2014
  • Magma
    [1+2*n+3*n^2+4*n^3+5*n^4+6*n^5+7*n^6+8*n^7+9*n^8: n in [0..20]]; // Vincenzo Librandi, Nov 09 2014
    
  • Mathematica
    CoefficientList[Series[(5 x^8 + 1548 x^7 + 31360 x^6 + 129620 x^5 + 148266 x^4 + 48316 x^3 + 3728 x^2 + 36 x + 1) / (1 - x)^9, {x, 0, 40}], x] (* Vincenzo Librandi, Nov 09 2014 *)
    With[{c=Total[Table[k n^(k-1),{k,9}]]},Table[c,{n,0,30}]] (* or *) LinearRecurrence[ {9,-36,84,-126,126,-84,36,-9,1},{1,45,4097,83653,757305,4272461,17736745,59409477,169826513},30] (* Harvey P. Dale, Jul 18 2017 *)
  • PARI
    vector(100,n,1 + 2*(n-1)+ 3*(n-1)^2 + 4*(n-1)^3 + 5*(n-1)^4 + 6*(n-1)^5 + 7*(n-1)^6 + 8*(n-1)^7 + 9*(n-1)^8) \\ Derek Orr, Nov 09 2014
    
  • Python
    A113630_list, m = [1], [362880, -1229760, 1607760, -1011480, 309816, -40752, 1584, -4, 1]
    for _ in range(10**3):
        for i in range(8):
            m[i+1]+= m[i]
        A113630_list.append(m[-1]) # Chai Wah Wu, Nov 09 2014
    

Formula

a(n) = 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6 + 8*n^7 + 9*n^8.
G.f.: -(5*x^8 +1548*x^7 +31360*x^6 +129620*x^5 +148266*x^4 +48316*x^3 +3728*x^2 +36*x +1) / (x -1)^9. - Colin Barker, May 08 2013

A123076 Numbers k such that p = 1 + 2k + 3k^2 + 4k^3 is prime.

Original entry on oeis.org

4, 12, 14, 18, 22, 24, 28, 34, 52, 62, 64, 78, 94, 104, 110, 118, 122, 132, 140, 144, 154, 158, 160, 178, 194, 204, 214, 218, 220, 234, 258, 262, 270, 272, 290, 294, 312, 314, 322, 344, 368, 370, 372, 382, 388, 424, 430, 440, 442, 454, 482, 494, 498, 518, 542
Offset: 1

Views

Author

Zak Seidov, Sep 27 2006

Keywords

Comments

Corresponding p's are in A123059.

Examples

			For k=4, 1 + 2k + 3k^2 + 4k^3 = 313 which is prime.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[542],PrimeQ[1+2#+3#^2+4#^3]&] (* James C. McMahon, Nov 15 2024 *)
  • PARI
    lista(m) = {for (n=1, m, if (isprime(1 + 2*n + 3*n^2 + 4*n^3), print1(n, ", ")););} \\ Michel Marcus, Apr 19 2013

A131464 a(n) = 4*n^3 - 3*n^2 + 2*n - 1.

Original entry on oeis.org

2, 23, 86, 215, 434, 767, 1238, 1871, 2690, 3719, 4982, 6503, 8306, 10415, 12854, 15647, 18818, 22391, 26390, 30839, 35762, 41183, 47126, 53615, 60674, 68327, 76598, 85511, 95090, 105359, 116342, 128063, 140546, 153815, 167894, 182807, 198578, 215231, 232790
Offset: 1

Views

Author

Mohammad K. Azarian, Jul 26 2007

Keywords

Crossrefs

Programs

  • Magma
    [4*n^3-3*n^2+2*n-1: n in [1..40]]; // Vincenzo Librandi, Feb 12 2013
    
  • Magma
    I:=[2, 23, 86, 215]; [n le 4 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Feb 12 2013
  • Mathematica
    CoefficientList[Series[(2 + 15 x + 6 x^2 + x^3)/(1 - x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Feb 12 2013 *)
    Table[4n^3-3n^2+2n-1,{n,40}] (* or *) LinearRecurrence[{4,-6,4,-1},{2,23,86,215},40] (* Harvey P. Dale, May 05 2018 *)

Formula

From Vincenzo Librandi, Feb 12 2013: (Start)
G.f.: x*(2 + 15*x + 6*x^2 + x^3)/(1 - x)^4.
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). (End)
E.g.f.: 1 - exp(x)*(1 - 3*x - 9*x^2 - 4*x^3). - Stefano Spezia, Dec 06 2024

A113531 a(n) = 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5.

Original entry on oeis.org

1, 21, 321, 2005, 7737, 22461, 54121, 114381, 219345, 390277, 654321, 1045221, 1604041, 2379885, 3430617, 4823581, 6636321, 8957301, 11886625, 15536757, 20033241, 25515421, 32137161, 40067565, 49491697, 60611301, 73645521
Offset: 0

Views

Author

Jonathan Vos Post, Jan 12 2006

Keywords

Comments

1 + 2x + 3x^2 + 4x^3 + 5x^4 + 6x^5 is the derivative of 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 = (n^7 - 1)/(n-1). a(6) = 1 + 2*6 + 3*6^2 + 4*6^3 + 5*6^4 + 6*6^5 = 54121 is prime, the smallest prime in the sequence. The next is a(a(1)) = a(21) = 1 + 2*21 + 3*21^2 + 4*21^3 + 5*21^4 + 6*21^5 = 25515421. Then a(24) = 49491697.

Crossrefs

Programs

  • Mathematica
    With[{eq=Total[# n^(#-1)&/@Range[6]]},Table[eq,{n,0,30}]] (* or *) LinearRecurrence[{6,-15,20,-15,6,-1},{1,21,321,2005,7737,22461},30] (* Harvey P. Dale, Nov 02 2011 *)
  • PARI
    for(n=0,50, print1(1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5, ", ")) \\ G. C. Greubel, Mar 15 2017

Formula

a(n) = 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5.
O.g.f.: 2064/(-1+x)^4+3/(-1+x)+2040/(-1+x)^5+132/(-1+x)^2+720/(-1+x)^6+872/(-1+x)^3 . - R. J. Mathar, Feb 26 2008
a(n) = 6*a(n-1)-15*a(n-2)+20*a(n-3)-15*a(n-4)+6*a(n-5)-a(n-6), a(0)=1, a(1)=21, a(2)=321, a(3)=2005, a(4)=7737, a(5)=22461. - Harvey P. Dale, Nov 02 2011

Extensions

Corrected by R. J. Mathar, Feb 26 2008

A113532 a(n) = 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6.

Original entry on oeis.org

1, 28, 769, 7108, 36409, 131836, 380713, 937924, 2054353, 4110364, 7654321, 13446148, 22505929, 36167548, 56137369, 84557956, 124076833, 177920284, 249972193, 344857924, 468033241, 625878268, 825796489, 1076318788
Offset: 0

Views

Author

Jonathan Vos Post, Jan 12 2006

Keywords

Comments

1 + 2x + 3x^2 + 4x^3 + 5x^4 + 6x^5 + 7*n^6 is the derivative of 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + x^7 = (x^8 - 1)/(x-1). a(2) = 1 + 2*2 + 3*2^2 + 4*2^3 + 5*2^4 + 6*2^5 + 7*2^6 = 769 is prime. Other primes begin a(6) = 380713, a(12) = 22505929, a(26) = 2236055953, a(38) = 21562615273, a(44) = 51802781449, a(52) = 140712620569.

Crossrefs

Programs

  • Mathematica
    Table[1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6, {n,0,50}] (* or *) LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {1, 28, 769, 7108, 36409, 131836, 380713}, 50] (* G. C. Greubel, Mar 15 2017 *)
  • PARI
    for(n=0,50, print1(1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6, ", ")) \\ G. C. Greubel, Mar 15 2017

Formula

a(n) = 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6.
O.g.f.: -12636/(-1+x)^4 -4/(-1+x) -21480/(-1+x)^5 -309/(-1+x)^2 -16920/(-1+x)^6 -3342/(-1+x)^3-5040/(-1+x)^7 . - R. J. Mathar, Feb 26 2008

A123077 Primes of the form (1+2n+3n^2+4n^3)/2.

Original entry on oeis.org

5, 71, 293, 7103, 32213, 40487, 50069, 87623, 161831, 211007, 238949, 337343, 852263, 922037, 1328447, 1421909, 1955399, 2607989, 3061703, 3744551, 4121087, 4318469, 4731941, 5400359, 5879231, 7198421, 9356927, 10400501, 10764863
Offset: 1

Views

Author

Zak Seidov, Sep 27 2006

Keywords

Comments

Corresponding n's are 1, 3, 5, 15, 25, 27, 29, 35, 43, 47, 49, 55, 75, 77, 87, 89, 99, 109, 115, 123, 127, 129, 133, 139, 143, 153, 167, 173, 175, 179, 183, 185, 195, 199, 207, 209, 227, 229, 239, 245, 257, 259, 269, 273, 283, 285, 299, 309, 315, 325, 327, 337, 347, 349, 357, 363, 369, 377, 379, 393, 399, 403, 409, 417, 425, 439, 523, 539, 545, 559, 567, 575, 587, 589, 593, 607, 623, 659, 687, 697, 699.
There are no primes of the form (1+2n+3n^2+4n^3)/3.

Crossrefs

Programs

  • Magma
    [a: n in [0..250] | IsPrime(a) where a is  (1 + 2*n + 3*n^2 + 4*n^3) div 2]; // Vincenzo Librandi, Mar 21 2013
  • Mathematica
    Select[Table[(1 + 2 n + 3 n^2 + 4 n^3)/2, {n, 0, 200}], PrimeQ] (* Vincenzo Librandi, Mar 21 2013 *)

A123100 Primes of the form (1+2n+3n^2+4n^3)/5.

Original entry on oeis.org

2, 197, 354677, 713357, 959597, 1256837, 3676037, 5168717, 7018997, 11945957, 15099437, 18764117, 25303637, 36170597, 42610877, 46099517, 49773557, 71092757, 75979997, 91974917, 110070437, 123365117, 161190317, 306442277
Offset: 1

Views

Author

Zak Seidov, Sep 27 2006

Keywords

Comments

All terms > 2 are congruent to 7 (mod 10).
Corresponding n's are: 1, 6, 76, 96, 106, 116, 166, 186, 206, 246, 266, 286, 316, 356, 376, 386, 396, 446, 456, 486, 516, 536, 586, 726, 736, 746, 766, 796, 846, 866, 906, 916, 1036, 1046, 1076, 1116, 1126, 1156, 1176, 1236, 1296, 1316, 1326, 1406, 1456, 1546, 1586, 1596, 1686, 1706, 1786, 1816, 1896, 1926, 1956, all are congruent to 1 (mod 5).

Crossrefs

Programs

  • Mathematica
    Select[Table[(1 + 2 n + 3 n^2 + 4 n^3)/5, {n, 0, 200}], PrimeQ] (* Vincenzo Librandi, Mar 21 2013 *)
Showing 1-10 of 14 results. Next