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 1-9 of 9 results.

A047848 Array A read by diagonals; n-th difference of (A(k,n), A(k,n-1),..., A(k,0)) is (k+2)^(n-1), for n=1,2,3,...; k=0,1,2,...

Original entry on oeis.org

1, 2, 1, 5, 2, 1, 14, 6, 2, 1, 41, 22, 7, 2, 1, 122, 86, 32, 8, 2, 1, 365, 342, 157, 44, 9, 2, 1, 1094, 1366, 782, 260, 58, 10, 2, 1, 3281, 5462, 3907, 1556, 401, 74, 11, 2, 1, 9842, 21846, 19532, 9332, 2802, 586, 92, 12, 2, 1, 29525, 87382, 97657, 55988, 19609, 4682, 821, 112, 13, 2, 1
Offset: 0

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Author

Keywords

Examples

			Array, A(n, k), begins as:
  1, 2,  5,  14,   41, ... = A007051.
  1, 2,  6,  22,   86, ... = A047849.
  1, 2,  7,  32,  157, ... = A047850.
  1, 2,  8,  44,  260, ... = A047851.
  1, 2,  9,  58,  401, ... = A047852.
  1, 2, 10,  74,  586, ... = A047853.
  1, 2, 11,  92,  821, ... = A047854.
  1, 2, 12, 112, 1112, ... = A047855.
  1, 2, 13, 134, 1465, ... = A047856.
  1, 2, 14, 158, 1886, ... = A196791.
  1, 2, 15, 184, 2381, ... = A196792.
Downward antidiagonals, T(n, k), begins as:
      1;
      2,     1;
      5,     2,     1;
     14,     6,     2,     1;
     41,    22,     7,     2,     1;
    122,    86,    32,     8,     2,    1;
    365,   342,   157,    44,     9,    2,   1;
   1094,  1366,   782,   260,    58,   10,   2,   1;
   3281,  5462,  3907,  1556,   401,   74,  11,   2,  1;
   9842, 21846, 19532,  9332,  2802,  586,  92,  12,  2, 1;
  29525, 87382, 97657, 55988, 19609, 4682, 821, 112, 13, 2, 1;
		

Crossrefs

Cf. A047857 (row sums), A196793 (main diagonal).

Programs

  • Magma
    A:= func< n,k | ((n+3)^k +n+1)/(n+2) >; // array A047848
    [A(k,n-k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jan 11 2025
    
  • Mathematica
    A[n_, k_]:= ((n+3)^k +n+1)/(n+2);
    A047848[n_, k_]:= A[k,n-k];
    Table[A047848[n,k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Jan 11 2025 *)
  • Python
    def A(n,k): return (pow(n+3,k) +n+1)//(n+2) # array A047848
    print(flatten([[A(k,n-k) for k in range(n+1)] for n in range(13)])) # G. C. Greubel, Jan 11 2025

Formula

A(n, k) = ((n+3)^k + n + 1)/(n+2). - Ralf Stephan, Feb 14 2004
From G. C. Greubel, Jan 11 2025: (Start)
T(n, k) = ((k+3)^(n-k) + k + 1)/(k+2) (antidiagonal triangle).
T(n, n) = A196793(n).
Sum_{k=0..n} T(n, k) = A047857(n). (End)

A227076 A triangle formed like Pascal's triangle, but with 5^n on the borders instead of 1.

Original entry on oeis.org

1, 5, 5, 25, 10, 25, 125, 35, 35, 125, 625, 160, 70, 160, 625, 3125, 785, 230, 230, 785, 3125, 15625, 3910, 1015, 460, 1015, 3910, 15625, 78125, 19535, 4925, 1475, 1475, 4925, 19535, 78125, 390625, 97660, 24460, 6400, 2950, 6400, 24460, 97660, 390625
Offset: 0

Views

Author

T. D. Noe, Aug 06 2013

Keywords

Comments

All rows except the zeroth are divisible by 5. Is there a closed-form formula for these numbers, as there is for binomial coefficients?

Examples

			Triangle begins as:
       1;
       5,     5;
      25,    10,    25;
     125,    35,    35,  125;
     625,   160,    70,  160,  625;
    3125,   785,   230,  230,  785, 3125;
   15625,  3910,  1015,  460, 1015, 3910, 15625;
   78125, 19535,  4925, 1475, 1475, 4925, 19535, 78125;
  390625, 97660, 24460, 6400, 2950, 6400, 24460, 97660, 390625;
		

Crossrefs

Cf. A007318 (Pascal's triangle), A228053 ((-1)^n on the borders).
Cf. A051601 (n on the borders), A137688 (2^n on borders).
Cf. A083585 (row sums: (8*5^n - 5*2^n)/3), A227074 (4^n edges), A227075 (3^n edges).
Cf. A000351.

Programs

  • Magma
    function T(n,k) // T = A227076
      if k eq 0 or k eq n then return 5^n;
      else return T(n-1,k) + T(n-1,k-1);
      end if;
    end function;
    [T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jan 10 2025
    
  • Maple
    A227076 := proc(n,k)
        if k = 0 or k = n then
            5^n ;
        elif k < 0 or k > n then
            0;
        else
            procname(n-1,k)+procname(n-1,k-1) ;
        end if;
    end proc: # R. J. Mathar, Aug 09 2013
  • Mathematica
    t = {}; Do[r = {}; Do[If[k == 0 || k == n, m = 5^n, m = t[[n, k]] + t[[n, k + 1]]]; r = AppendTo[r, m], {k, 0, n}]; AppendTo[t, r], {n, 0, 10}]; t = Flatten[t]
  • Python
    from sage.all import *
    @CachedFunction
    def T(n,k): # T = A227076
        if k==0 or k==n: return pow(5,n)
        else: return T(n-1,k) + T(n-1,k-1)
    print(flatten([[T(n,k) for k in range(n+1)] for n in range(13)])) # G. C. Greubel, Jan 10 2025

Formula

From R. J. Mathar, Aug 09 2013: (Start)
T(n,0) = 5^n.
T(n,1) = 5*A047850(n-1).
T(n,2) = 5*(5^n/80 + 3*n/4 + 51/16).
T(n,3) = 5*(5^n/320 + 45*n/16 + 3*n^2/8 + 819/64). (End)
Sum_{k=0..n} (-1)^k*T(n, k) = 20*(1+(-1)^n)*A009969(floor((n-1)/2)) - (3/5)*[n = 0]. - G. C. Greubel, Jan 10 2025

A132079 a(n) = (5^n + 3)/2.

Original entry on oeis.org

2, 4, 14, 64, 314, 1564, 7814, 39064, 195314, 976564, 4882814, 24414064, 122070314, 610351564, 3051757814, 15258789064, 76293945314, 381469726564, 1907348632814, 9536743164064, 47683715820314
Offset: 0

Views

Author

Mohit Maheshwari (mohitmahe1989(AT)gmail.com), Oct 30 2007

Keywords

Comments

(5^n + 3)/2 is always divisible by 2 and the next value can be generated by appending 4 at the ones place and adding the rest of the number with the respective power of 5. For example, 314 can be generated after 64 by just writing 4 at the ones place and adding 5^2 to 6 to get 31 and appending 31 to 4 to get 314.

Crossrefs

Cf. A047850.

Programs

Formula

From Elmo R. Oliveira, Dec 21 2023: (Start)
a(n) = 2*A047850(n).
a(n) = 5*a(n-1) - 6 for n>0.
a(n) = 6*a(n-1) - 5*a(n-2) for n>1.
G.f.: (2-8*x)/((1-x)*(1-5*x)).
E.g.f.: exp(x)*(exp(4*x) + 3)/2. (End)

Extensions

Offset changed from 4 to 0; corrected and extended by Vincenzo Librandi, May 02 2011

A123490 Triangle whose k-th column satisfies a(n) = (k+3)*a(n-1)-(k+2)*a(n-2).

Original entry on oeis.org

1, 2, 1, 4, 2, 1, 8, 5, 2, 1, 16, 14, 6, 2, 1, 32, 41, 22, 7, 2, 1, 64, 122, 86, 32, 8, 2, 1, 128, 365, 342, 157, 44, 9, 2, 1, 256, 1094, 1366, 782, 260, 58, 10, 2, 1, 512, 3281, 5462, 3907, 1556, 401, 74, 11, 2, 1, 1024, 9842, 21846, 19532, 9332, 2802, 586, 92, 12, 2, 1
Offset: 0

Views

Author

Paul Barry, Oct 01 2006

Keywords

Examples

			Triangle begins
     1;
     2,    1;
     4,    2,     1;
     8,    5,     2,     1;
    16,   14,     6,     2,    1;
    32,   41,    22,     7,    2,    1;
    64,  122,    86,    32,    8,    2,   1;
   128,  365,   342,   157,   44,    9,   2,  1;
   256, 1094,  1366,   782,  260,   58,  10,  2,  1;
   512, 3281,  5462,  3907, 1556,  401,  74, 11,  2, 1;
  1024, 9842, 21846, 19532, 9332, 2802, 586, 92, 12, 2, 1;
		

Crossrefs

Columns include A000079, A007051, A047849, A047850, A047851.
Cf. A047848, A103439 (row sums), A123491 (diagonal sums).

Programs

  • Magma
    [((k+2)^(n-k) +k)/(k+1): k in [0..n], n in [0..12]]; // G. C. Greubel, Jun 15 2021
    
  • Mathematica
    Table[((k+2)^(n-k) +k)/(k+1), {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Oct 14 2017 *)
  • PARI
    for(n=0, 10, for(k=0,n, print1(((k+2)^(n-k)+k)/(k+1), ", "))) \\ G. C. Greubel, Oct 14 2017
    
  • Sage
    flatten([[((k+2)^(n-k) +k)/(k+1) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jun 15 2021

Formula

Column k has g.f.: x^k*(1-x(1+k))/((1-x)*(1-x(2+k))).
T(n,k) = ((k+2)^(n-k) + k)/(k+1), for 0 <= k <= n.
Sum_{k=0..n} T(n, k) = A103439(n+1).
Sum_{k=0..floor(n/2)} T(n-k, k) = A123491(n).

A153776 Sequence S such that 1 is in S and if x is in S, then 5x-3 and 5x-1 are in S.

Original entry on oeis.org

1, 2, 4, 7, 9, 17, 19, 32, 34, 42, 44, 82, 84, 92, 94, 157, 159, 167, 169, 207, 209, 217, 219, 407, 409, 417, 419, 457, 459, 467, 469, 782, 784, 792, 794, 832, 834, 842, 844, 1032, 1034, 1042, 1044, 1082, 1084, 1092, 1094, 2032, 2034, 2042, 2044, 2082, 2084
Offset: 1

Views

Author

Clark Kimberling, Jan 02 2009

Keywords

Comments

Subsequences include A047850, A083065.
First generation: 1
2nd generation: 2, 4
3rd generation: 7, 9, 17, 19
4th generation: 32, 34, 42, 44, 82, 84, 92, 94
Does every generation contain p or 2p for some prime p?

Crossrefs

Programs

  • Mathematica
    nxt[n_] := Flatten[5 # + {-3, -1} & /@ n]; Union[Flatten[NestList[nxt, {1}, 5]]] (* G. C. Greubel, Aug 28 2016 *)

A196791 a(n) = A047848(9, n).

Original entry on oeis.org

1, 2, 14, 158, 1886, 22622, 271454, 3257438, 39089246, 469070942, 5628851294, 67546215518, 810554586206, 9726655034462, 116719860413534, 1400638324962398, 16807659899548766, 201691918794585182, 2420303025535022174, 29043636306420266078, 348523635677043192926
Offset: 0

Views

Author

Vincenzo Librandi, Oct 11 2011

Keywords

Crossrefs

Cf. A001021 (first differences).

Programs

  • Magma
    [(12^n+10)/11: n in [0..20]];
    
  • Mathematica
    LinearRecurrence[{13,-12},{1,2},30] (* Harvey P. Dale, Sep 07 2015 *)
    (12^Range[0,40] +10)/11 (* G. C. Greubel, Jan 17 2025 *)
  • Python
    def A196791(n): return (pow(12, n) + 10)//11
    print([A196791(n) for n in range(41)]) # G. C. Greubel, Jan 17 2025

Formula

a(n) = (12^n + 10)/11.
a(n) = 12*a(n-1) - 10, with a(0) = 1.
G.f.: (1-11*x)/((1-x)*(1-12*x)). - Bruno Berselli, Oct 11 2011
From Elmo R. Oliveira, Aug 30 2024: (Start)
E.g.f.: exp(x)*(exp(11*x) + 10)/11.
a(n) = 13*a(n-1) - 12*a(n-2) for n > 1. (End)

A196792 a(n) = A047848(10, n).

Original entry on oeis.org

1, 2, 15, 184, 2381, 30942, 402235, 5229044, 67977561, 883708282, 11488207655, 149346699504, 1941507093541, 25239592216022, 328114698808275, 4265491084507564, 55451384098598321, 720867993281778162, 9371283912663116095, 121826690864620509224, 1583746981240066619901
Offset: 0

Views

Author

Vincenzo Librandi, Oct 11 2011

Keywords

Crossrefs

Cf. A001022 (first differences).

Programs

  • Magma
    [(13^n+11)/12: n in [0..20]];
    
  • Mathematica
    (13^Range[0,40] +11)/12 (* G. C. Greubel, Jan 17 2025 *)
  • Python
    def A196792(n): return (pow(13, n) + 11)//12
    print([A196792(n) for n in range(41)]) # G. C. Greubel, Jan 17 2025

Formula

a(n) = (13^n + 11)/12.
a(n) = 13*a(n-1) - 11, with a(0) = 1.
G.f.: (1-12*x)/((1-x)*(1-13*x)). - Bruno Berselli, Oct 11 2011
From Elmo R. Oliveira, Aug 30 2024: (Start)
E.g.f.: exp(x)*(exp(12*x) + 11)/12.
a(n) = 14*a(n-1) - 13*a(n-2) for n > 1. (End)

A196793 a(n) = A047848(n, n).

Original entry on oeis.org

1, 2, 7, 44, 401, 4682, 66431, 1111112, 21435889, 469070942, 11488207655, 311505013052, 9267595563617, 300239975158034, 10523614159962559, 396861212733968144, 16024522975978953761, 689852631578947368422, 31544039619835776489479
Offset: 0

Views

Author

Vincenzo Librandi, Oct 11 2011

Keywords

Crossrefs

Programs

Formula

a(n) = ((n+3)^n + n + 1)/(n+2).

A166124 Triangle, read by rows, given by [0,1/2,1/2,0,0,0,0,0,0,0,...] DELTA [2,-1,0,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938.

Original entry on oeis.org

1, 0, 2, 0, 1, 2, 0, 1, 1, 2, 0, 1, 1, 1, 2, 0, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2
Offset: 0

Views

Author

Philippe Deléham, Oct 07 2009

Keywords

Examples

			Triangle begins :
1 ;
0,2 ;
0,1,2 ;
0,1,1,2 ;
0,1,1,1,2 ;
0,1,1,1,1,2 ;
0,1,1,1,1,1,2 ; ...
		

Formula

Sum_{k, 0<=k<=n} T(n,k)*x^(n-k)= A166122(n), A166114(n), A084222(n), A084247(n), A000034(n), A040000(n), A000027(n+1), A000079(n), A007051(n), A047849(n), A047850(n), A047851(n), A047852(n), A047853(n), A047854(n), A047855(n), A047856(n) for x= -5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10,11 respectively.
Sum_{k, 0<=k<=n} T(n,k)*x^k= A000007(n), A000027(n+1), A033484(n), A134931(n), A083597(n) for x= 0,1,2,3,4 respectively.
T(n,k)= A166065(n,k)/2^(n-k).
G.f.: (1-x+x*y)/(1-x-x*y+x^2*y). - Philippe Deléham, Nov 09 2013
T(n,k) = T(n-1,k) + T(n-1,k-1) - T(n-2,k-1), T(0,0) = 1, T(1,0) = 0, T(1,1) = 2, T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Nov 09 2013
Showing 1-9 of 9 results.