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 12 results. Next

A245318 Numbers k that divide 2^k + 5.

Original entry on oeis.org

1, 7, 133, 1517, 11761, 676333, 1484413, 3627557, 10289371, 1449045241, 2433687407, 12309023183, 29013950411, 11701492535299, 223598572318157, 362232879754103
Offset: 1

Views

Author

Derek Orr, Jul 17 2014

Keywords

Comments

No other terms below 10^15. Some large terms: 37367159696063084325121, 1637537600494693555095121, 50692913747901869910332539, 407*(2^407+5)/1125038874668278099 (108 digits). - Max Alekseyev, Sep 22 2016

Examples

			2^7 + 5 = 133 is divisible by 7. Thus 7 is a term of this sequence.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[10^5], Divisible[2^# + 5, #] &] (* Robert Price, Oct 12 2018 *)
  • PARI
    for(n=1,10^9,if(Mod(2,n)^n==Mod(-5,n),print1(n,", ")))

Extensions

a(10)-a(13) from Lars Blomberg, Nov 05 2014
a(14)-a(16) from Max Alekseyev, Oct 09 2016

A254368 a(n) = 5*2^n + 3^n + 15.

Original entry on oeis.org

21, 28, 44, 82, 176, 418, 1064, 2842, 7856, 22258, 64184, 187402, 551936, 1635298, 4864904, 14512762, 43374416, 129795538, 388731224, 1164882922, 3492027296, 10470838978, 31402031144, 94185121882, 282513422576, 847456381618, 2542201372664, 7626268573642, 22878134632256, 68633061719458, 205896500803784, 617684133702202
Offset: 0

Views

Author

Luciano Ancora, Jan 29 2015

Keywords

Comments

This is the sequence of third terms of "fifth partial sums of m-th powers".

Crossrefs

Programs

  • Mathematica
    Table[5 2^n + 3^n + 15, {n, 0, 30}] (* Bruno Berselli, Jan 30 2015 *)
    LinearRecurrence[{6,-11,6},{21,28,44},40] (* Harvey P. Dale, Apr 26 2022 *)
  • PARI
    vector(30, n, n--; 5*2^n + 3^n + 15) \\ Colin Barker, Jan 30 2015

Formula

G.f.: -(107*x^2-98*x+21) / ((x-1)*(2*x-1)*(3*x-1)). - Colin Barker, Jan 30 2015
a(n) = 6*a(n-1)-11*a(n-2)+6*a(n-3). - Colin Barker, Jan 30 2015

A254369 a(n) = 15*2^n + 4^n + 5*3^n + 35.

Original entry on oeis.org

56, 84, 156, 354, 936, 2754, 8736, 29274, 102216, 368274, 1359216, 5110794, 19495896, 75203394, 292596096, 1145977914, 4511183976, 17827536114, 70660511376, 280697078634, 1116961278456, 4450379734434, 17749154257056, 70839585900954, 282887376051336, 1130136853206354, 4516309963145136, 18052528510172874, 72171982026734616
Offset: 0

Views

Author

Luciano Ancora, Jan 29 2015

Keywords

Comments

This is the sequence of fourth terms of "fifth partial sums of m-th powers".

Crossrefs

Programs

  • Mathematica
    Table[15 2^n + 4^n + 5 3^n + 35, {n, 0, 30}] (* Bruno Berselli, Jan 30 2015 *)
    LinearRecurrence[{10,-35,50,-24},{56,84,156,354},30] (* Harvey P. Dale, Dec 04 2020 *)
  • PARI
    vector(30, n, n--; 15*2^n + 4^n + 5*3^n + 35) \\ Colin Barker, Jan 30 2015

Formula

G.f.: -2*(533*x^3-638*x^2+238*x-28) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)). - Colin Barker, Jan 30 2015
a(n) = 10*a(n-1)-35*a(n-2)+50*a(n-3)-24*a(n-4). - Colin Barker, Jan 30 2015

A254370 a(n) = 35*2^n + 5*4^n + 15*3^n + 5^n + 70.

Original entry on oeis.org

126, 210, 450, 1200, 3750, 13080, 49350, 197400, 825750, 3577080, 15930150, 72528600, 336141750, 1580449080, 7518010950, 36102667800, 174710721750, 850780489080, 4164115131750, 20465328135000, 100917328245750, 498984369457080, 2472617583932550
Offset: 0

Views

Author

Luciano Ancora, Jan 30 2015

Keywords

Comments

This is the sequence of fifth terms of "fifth partial sums of m-th powers".

Crossrefs

Programs

  • Mathematica
    Table[35 2^n + 5 4^n + 15 3^n + 5^n + 70, {n, 0, 30}] (* Bruno Berselli, Jan 30 2015 *)
  • PARI
    vector(30, n, n--; 35*2^n + 5*4^n + 15*3^n + 5^n + 70) \\ Colin Barker, Jan 30 2015

Formula

G.f.: -6*(1879*x^4-2675*x^3+1335*x^2-280*x+21) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)). - Colin Barker, Jan 30 2015
a(n) = 15*a(n-1)-85*a(n-2)+225*a(n-3)-274*a(n-4)+120*a(n-5). - Colin Barker, Jan 30 2015

A224701 Table read by antidiagonals of numbers of form (2^n - 1)*2^(m+3) + 5 where n>=1, m>=1.

Original entry on oeis.org

21, 37, 53, 69, 101, 117, 133, 197, 229, 245, 261, 389, 453, 485, 501, 517, 773, 901, 965, 997, 1013, 1029, 1541, 1797, 1925, 1989, 2021, 2037, 2053, 3077, 3589, 3845, 3973, 4037, 4069, 4085, 4101, 6149, 7173, 7685, 7941, 8069, 8133, 8165, 8181, 8197, 12293, 14341, 15365, 15877, 16133
Offset: 1

Views

Author

Brad Clardy, Apr 16 2013

Keywords

Comments

The table has row labels 2^n - 1 and column labels 2^(m+3). The table entry is row*col + 5. A MAGMA program is provided that generates the numbers in a table format. The sequence is read along the antidiagonals starting from the top left corner. Using the lexicographic ordering of A057555 the sequence is:
A(n) = Table(i,j) with (i,j)=(1,1),(1,2),(2,1),(1,3),(2,2),(3,1)...
+5 | 16 32 64 128 256 512 1024 ...
----|-------------------------------------------
1 | 21 37 69 133 261 517 1029
3 | 53 101 197 389 773 1541 3077
7 | 117 229 453 901 1797 3589 7173
15 | 245 485 965 1925 3845 7685 15365
31 | 501 997 1989 3973 7941 15877 31749
63 | 1013 2021 4037 8069 16133 32261 64517
127 | 2037 4069 8133 16261 32517 65029 130053
...
All of these numbers have the following property: let m be a member of A(n); if a sequence B(n) = all i such that i XOR (m - 1) = i - (m - 1), then the differences between successive members of B(n) is a repeating series
of 1,1,1,5 ending with 1,1,1 and the last difference in the pattern m. The total number of 1's and 5's in the pattern is 2^(j+2) - 1, where j is the column index.
As an example, consider A(1), which is 21; the sequence B(n) where i XOR 20 = i - 20 starts as 20, 21, 22, 23, 28, 29, 30, 31, 52, ... with successive differences of 1, 1, 1, 5, 1, 1, 1, 21.
for A(2), which is 37, the sequence B(n) where i XOR 36 = i - 36 starts as 36, 37, 38, 39, 44, 45, 46, 47, 52, 53, 54, 55, 60, 61, 62, 63, 100, ... with successive differences of 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 1, 37.

Crossrefs

Cf. A057555 (lexicographic ordering).
Rows: A168614(i=1), n>=4.
Cols: A220087(j=2), n>=6.

Programs

  • Magma
    //program generates values in a table form, row labels of 2^i -1
    for i:=1 to 10 do
        m:=2^i - 1;
        m, [ m*2^(n+3) +5 : n in [1..10]];
    end for;
    //program generates sequence in lexicographic ordering of A057555, read
    //along antidiagonals from top. Primes in the sequence are marked with *.
    for i:=2 to 18 do
        for j:=1 to i-1 do
           m:=2^j -1;
           k:=m*2^(3+i-j) + 5;
           if IsPrime(k) then k, "*";
              else k;
           end if;
        end for;
    end for;

Formula

a(n) = 2^(A057555(2*n - 1))*2^(A057555(2*n) + 3) + 5 for n>=1.

A242475 a(n) = 2^n + 8.

Original entry on oeis.org

9, 10, 12, 16, 24, 40, 72, 136, 264, 520, 1032, 2056, 4104, 8200, 16392, 32776, 65544, 131080, 262152, 524296, 1048584, 2097160, 4194312, 8388616, 16777224, 33554440, 67108872, 134217736, 268435464, 536870920, 1073741832
Offset: 0

Views

Author

Vincenzo Librandi, May 20 2014

Keywords

Crossrefs

Programs

  • Magma
    [2^n+8: n in [0..40]];
  • Mathematica
    Table[2^n + 8, {n, 0, 40}] (* or *) CoefficientList[Series[(9 - 17 x)/((1 - x) (1 - 2 x)),{x, 0, 30}], x]
    LinearRecurrence[{3,-2},{9,10},40] (* Harvey P. Dale, May 21 2025 *)

Formula

G.f.: (9 - 17*x)/((1 - x)*(1 - 2*x)).
a(n) = 2*a(n-1) - 8 = 3*a(n-1) - 2*a(n-2).
a(n) = A052548(n)+6 = A140504(n)+4 = A153972(n)+2.
E.g.f.: exp(2*x) + 8*exp(x). - Elmo R. Oliveira, Nov 11 2023

A246139 a(n) = 2^n + 10.

Original entry on oeis.org

11, 12, 14, 18, 26, 42, 74, 138, 266, 522, 1034, 2058, 4106, 8202, 16394, 32778, 65546, 131082, 262154, 524298, 1048586, 2097162, 4194314, 8388618, 16777226, 33554442, 67108874, 134217738, 268435466, 536870922, 1073741834, 2147483658, 4294967306
Offset: 0

Views

Author

Vincenzo Librandi, Aug 18 2014

Keywords

Comments

First trisection of A085688. [Bruno Berselli, Aug 19 2014]

Crossrefs

Cf. Sequences of the form 2^n + k: A000079 (k=0), A000051 (k=1), A052548 (k=2), A062709 (k=3), A140504 (k=4), A168614 (k=5), A153972 (k=6), A168415 (k=7), A242475 (k=8), A188165 (k=9), this sequence (k=10).
Cf. A085688.

Programs

  • Magma
    [2^n+10: n in [0..40]];
    
  • Mathematica
    Table[2^n + 10, {n, 0, 40}]
  • PARI
    vector(50, n, 2^(n-1)+10) \\ Derek Orr, Aug 18 2014

Formula

G.f.: (11 - 21*x)/(1 - 3*x + 2*x^2).
a(n) = A000079(n) + 10.
a(n) = 3*a(n-1) - 2*a(n-2) for n > 1.
E.g.f.: exp(2*x) + 10*exp(x). - Elmo R. Oliveira, Nov 11 2023

A254467 a(n) = 15*4^n + 70*2^n + 35*3^n + 5^(n+1) + 6^n + 126.

Original entry on oeis.org

252, 462, 1122, 3432, 12342, 49632, 216342, 1001952, 4863462, 24500352, 127161462, 676195872, 3668030982, 20227217472, 113076824982, 639383508192, 3649985092902, 21003583828992, 121677813214902, 708891056106912, 4149610383537222
Offset: 0

Views

Author

Luciano Ancora, Jan 31 2015

Keywords

Comments

This is the sequence of sixth terms of "fifth partial sums of m-th powers".

Crossrefs

Programs

  • Mathematica
    Table[15×4^n+70×2^n+35×3^n+5^(n+1)+6^n+126, {n, 0, 25}] (* Michael De Vlieger, Jan 31 2015 *)
    LinearRecurrence[{21,-175,735,-1624,1764,-720},{252,462,1122,3432,12342,49632},30] (* Harvey P. Dale, Jul 16 2018 *)
  • PARI
    vector(30, n, n--; 15*4^n + 70*2^n + 35*3^n + 5^(n+1) + 6^n + 126) \\ Colin Barker, Jan 31 2015

Formula

G.f.: -6*(21310*x^5 -34383*x^4 +20750*x^3 -5920*x^2 +805*x -42) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)). - Colin Barker, Jan 31 2015
a(n) = 21*a(n-1)-175*a(n-2)+735*a(n-3)-1624*a(n-4)+1764*a(n-5)-720*a(n-6). - Colin Barker, Jan 31 2015

A254468 a(n) = 35*4^n + 126*2^n + 70*3^n + 15*5^n + 5*6^n + 7^n + 210.

Original entry on oeis.org

462, 924, 2508, 8646, 35112, 159654, 787968, 4137966, 22807752, 130656534, 772253328, 4683193086, 29012227992, 182964472614, 1171328741088, 7594839621006, 49780643849832, 329318254755894, 2195866174387248, 14741498331453726, 99542297086537272
Offset: 0

Views

Author

Luciano Ancora, Jan 31 2015

Keywords

Comments

This is the sequence of seventh terms of "fifth partial sums of m-th powers".

Crossrefs

Programs

  • Mathematica
    Table[35 4^n + 126 2^n + 70 3^n + 15 5^n + 5 6^n + 7^n + 210, {n, 0, 25}] (* Michael De Vlieger, Jan 31 2015 *)
    LinearRecurrence[{28,-322,1960,-6769,13132,-13068,5040},{462,924,2508,8646,35112,159654,787968},30] (* Harvey P. Dale, Dec 29 2019 *)
  • PARI
    vector(30, n, n--; 35*4^n + 126*2^n + 70*3^n + 15*5^n + 5*6^n + 7^n + 210) \\ Colin Barker, Jan 31 2015

Formula

G.f.: -6*(259610*x^6 -461263*x^5 +319473*x^4 -111595*x^3 +20900*x^2 -2002*x +77) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)). - Colin Barker, Jan 31 2015
a(n) = 28*a(n-1) -322*a(n-2) +1960*a(n-3) -6769*a(n-4) +13132*a(n-5) -13068*a(n-6) +5040*a(n-7). - Colin Barker, Jan 31 2015

A248604 Numbers a(n) which are the minimum number of moves needed in a variation of the tower of Hanoi with 4 towers and n disks.

Original entry on oeis.org

1, 3, 5, 9, 13, 21, 37, 69, 133, 261, 517, 1029, 2053, 4101, 8197, 16389, 32773, 65541, 131077, 262149, 524293, 1048581, 2097157, 4194309, 8388613, 16777221, 33554437, 67108869, 134217733, 268435461, 536870917, 1073741829, 2147483653, 4294967301, 8589934597
Offset: 1

Views

Author

Aaron C. Horak, Oct 09 2014

Keywords

Crossrefs

Cf. A168614.

Programs

  • Mathematica
    LinearRecurrence[{3,-2},{1,3,5,9,13},40] (* Harvey P. Dale, May 10 2019 *)

Formula

a(1)=1; a(2)=3; a(3)=5; a(n) = 5 + 2^(n-2) for n > 3.
G.f.: x*(1 - 2*x^2 - 4*x^4)/((1 - x)*(1 - 2*x)). - Stefano Spezia, May 15 2023

Extensions

More terms from Harvey P. Dale, May 10 2019
Showing 1-10 of 12 results. Next