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.

Previous Showing 11-19 of 19 results.

A138199 a(n) = 14^(2*n+1) + 3^(2*n+1).

Original entry on oeis.org

17, 2771, 538067, 105415691, 20661066467, 4049565346811, 793714774848467, 155568095572161131, 30491346729460336067, 5976303958950076658651, 1171355575953997682201267, 229585692886981589625399371, 44998795805848373961803836067, 8819763977946281138070581903291
Offset: 0

Views

Author

Reinhard Zumkeller, Mar 05 2008

Keywords

Comments

Subsequence of A008599; A138200(n) = a(n)/17.

References

  • F. Ischebeck, Einladung zur Zahlentheorie (BI Wissenschaftsverlag 1992), Aufgabe 7, p. 18.

Crossrefs

Programs

  • Magma
    [14^(2*n+1)+3^(2*n+1): n in [0..20]]; // Vincenzo Librandi, Dec 27 2010
  • Mathematica
    Table[c=2n+1;14^c+3^c,{n,0,20}] (* or *) LinearRecurrence[{205,-1764},{17,2771},30] (* Harvey P. Dale, Aug 13 2013 *)
    CoefficientList[Series[14/(1 - 196 x) + 3/(1 - 9 x), {x, 0, 25}], x] (* Vincenzo Librandi, May 23 2014 *)

Formula

a(0)=17, a(1)=2771; a(n) = 205*a(n-1)-1764*a(n-2). - Harvey P. Dale, Aug 13 2013
G.f.: 14/(1-196*x)+3/(1-9*x). -Harvey P. Dale, Aug 13 2013

Extensions

Corrected and extended by Harvey P. Dale, Aug 13 2013

A309131 Triangle read by rows: T(n, k) = (n - k)*prime(1 + k), with 0 <= k < n.

Original entry on oeis.org

2, 4, 3, 6, 6, 5, 8, 9, 10, 7, 10, 12, 15, 14, 11, 12, 15, 20, 21, 22, 13, 14, 18, 25, 28, 33, 26, 17, 16, 21, 30, 35, 44, 39, 34, 19, 18, 24, 35, 42, 55, 52, 51, 38, 23, 20, 27, 40, 49, 66, 65, 68, 57, 46, 29, 22, 30, 45, 56, 77, 78, 85, 76, 69, 58, 31
Offset: 1

Views

Author

Stefano Spezia, Jul 14 2019

Keywords

Comments

T(n, k) is the k-superdiagonal sum of an n X n Toeplitz matrix M(n) whose first row consists of successive prime numbers prime(1), ..., prime(n).
The h-th subdiagonal of the triangle T gives the primes multiplied by (h + 1).
The k-th column of the triangle T gives the multiples of prime(1 + k).
Also array A(n, k) = n*prime(1 + k) read by ascending antidiagonals, with 0 <= k < n. - Michel Marcus, Jul 15 2019

Examples

			The triangle T(n, k) begins:
---+-----------------------------------------------------
n\k|    0     1     2     3     4     5     6     7     8
---+-----------------------------------------------------
1  |    2
2  |    4     3
3  |    6     6     5
4  |    8     9    10     7
5  |   10    12    15    14    11
6  |   12    15    20    21    22    13
7  |   14    18    25    28    33    26    17
8  |   16    21    30    35    44    39    34    19
9  |   18    24    35    42    55    52    51    38    23
...
For n = 3 the matrix M(3) is
          2,         3,         5
    M_{2,1},         2,         3
    M_{3,1},   M_{3,2},         2
and therefore T(3, 0) = 2 + 2 + 2 = 6, T(3, 1) = 3 + 3 = 6, and T(3, 2) = 5.
		

Crossrefs

Cf. A000040: diagonal; A001747: 1st subdiagonal; A001748: 2nd subdiagonal; A001749: 3rd subdiagonal; A001750: 4th subdiagonal; A005843: 0th column; A008585: 1st column; A008587: 2nd column; A008589: 3rd column; A008593: 4th column; A008595: 5th column; A008599: 6th column; A008601: 7th column; A014148: row sums; A138636: 5th subdiagonal; A272470: 6th subdiagonal.

Programs

  • Magma
    [[(n-k)*NthPrime(1+k): k in [0..n-1]]: n in [1..11]]; // triangle output
    
  • Maple
    a:=(n, k)->(n-k)*ithprime(1+k): seq(seq(a(n, k), k=0..n-1), n=1..11);
  • Mathematica
    Flatten[Table[(n-k)*Prime[1+k],{n,1,11},{k,0,n-1}]]
  • PARI
    T(n, k) = (n - k)*prime(1 + k);
    tabl(nn) = for(n=1, nn, for(k=0, n-1, print1(T(n, k), ", ")); print); \\ triangle output
    
  • Sage
    [[(n-k)*Primes().unrank(k) for k in (0..n-1)] for n in (1..11)] # triangle output

Formula

T(n, k) = A025581(n, k)*A000040(1 + k).

A154612 a(n) = 17*n + 7.

Original entry on oeis.org

7, 24, 41, 58, 75, 92, 109, 126, 143, 160, 177, 194, 211, 228, 245, 262, 279, 296, 313, 330, 347, 364, 381, 398, 415, 432, 449, 466, 483, 500, 517, 534, 551, 568, 585, 602, 619, 636, 653, 670, 687, 704, 721, 738, 755, 772, 789, 806, 823, 840, 857, 874, 891
Offset: 0

Views

Author

Vincenzo Librandi, Jan 15 2009

Keywords

Comments

a(n)^4 = Sum_{j=0..(16*n*(17*n+14)+46)} (-1)^j*(119*n^2 + 98*n + 20 + j)^2. - Bruno Berselli, Apr 30 2010

Examples

			For n=5, a(5)^4 = 92^4 = 71639296 = 3485^2-3486^2+3487^2-..+11449^2-11450^2+11451^2. - _Bruno Berselli_, Apr 30 2010
		

Crossrefs

Sequences of the form 17*n+q: A361692 (q=-1), A008599 (q=0), A215137 (q=1), this sequence (q=7).

Programs

Formula

G.f.: (7+10*x)/(1-x)^2. - Colin Barker, Jan 09 2012
a(n) = 2*a(n-1) - a(n-2). - Vincenzo Librandi, Feb 26 2012
E.g.f.: (7 + 17*x)*exp(x). - G. C. Greubel, May 31 2024

Extensions

Offset corrected by Bruno Berselli, Aug 16 2010

A217558 Split-and-swap on 8-bit integers.

Original entry on oeis.org

0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 1, 17, 33, 49, 65, 81, 97, 113, 129, 145, 161, 177, 193, 209, 225, 241, 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162, 178, 194, 210, 226, 242, 3, 19, 35, 51, 67, 83, 99, 115, 131, 147, 163, 179, 195, 211, 227, 243
Offset: 0

Views

Author

Jon Perry, Oct 06 2012

Keywords

Comments

Split-and-swap consists of spliting a binary word into two halves and swapping the parts over to form a new word, for example 11001010 becomes 10101100.
There are 256 terms to the sequence. - Harvey P. Dale, Jul 14 2015
Fixed points are the multiples of 17 (A008599) in {0..255}. - Alois P. Heinz, May 02 2024

Examples

			a(17)=17 because 17 is 00010001 which is invariant over the SaS rule.
a(19)=49 because 00010011 becomes 00110001.
		

Crossrefs

Cf. A008599.

Programs

  • JavaScript
    for (i=0;i<16;i++)
    for (j=0;j<16;j++)
    document.write(j*16+i+", ");
    
  • Mathematica
    FromDigits[#,2]&/@(Join[Take[#,-4],Take[#,4]]&/@Select[Tuples[{0,1},8], Length[#] ==8 &]) (* Harvey P. Dale, Jul 14 2015 *)
  • PARI
    A217558(n)=[1,16]*divrem(n,16) \\ - M. F. Hasler, Oct 07 2012

A361692 a(n) = 17*n - 1.

Original entry on oeis.org

16, 33, 50, 67, 84, 101, 118, 135, 152, 169, 186, 203, 220, 237, 254, 271, 288, 305, 322, 339, 356, 373, 390, 407, 424, 441, 458, 475, 492, 509, 526, 543, 560, 577, 594, 611, 628, 645, 662, 679, 696, 713, 730, 747, 764, 781, 798, 815, 832, 849, 866, 883, 900, 917, 934, 951, 968, 985, 1002, 1019
Offset: 1

Views

Author

Leo Tavares, Mar 20 2023

Keywords

Crossrefs

Programs

  • Mathematica
    17*Range[100] - 1 (* Paolo Xausa, Aug 30 2024 *)
    LinearRecurrence[{2,-1},{16,33},90] (* Harvey P. Dale, Jun 03 2025 *)

Formula

a(n) = 17*n - 1 = A008599(n) - 1.
a(n) = 2*A008590(n) + n - 1.
a(n) = A008590(n) + A017257(n-1).
From Elmo R. Oliveira, Apr 03 2025: (Start)
G.f.: x*(16 + x)/(x - 1)^2.
E.g.f.: exp(x)*(17*x - 1) + 1.
a(n) = 2*a(n-1) - a(n-2) for n > 2. (End)

A166391 Multiples of 17 whose reversal + 1 is also a multiple of 17.

Original entry on oeis.org

187, 238, 1870, 1921, 2380, 2431, 2754, 2805, 3264, 3315, 3587, 3638, 4097, 4148, 5661, 5712, 5984, 6171, 6222, 6494, 6545, 6868, 6919, 7055, 7106, 7378, 7429, 8891, 8942, 9452, 9503, 9775, 9826
Offset: 1

Views

Author

Claudio Meller, Oct 13 2009

Keywords

Crossrefs

Subsequence of A008599.

Programs

  • Mathematica
    Select[17 Range[6!], Divisible[FromDigits[Reverse[IntegerDigits[#]]] + 1, 17] &] (* G. C. Greubel, May 12 2016 *)

A303302 a(n) = 34*n^2.

Original entry on oeis.org

0, 34, 136, 306, 544, 850, 1224, 1666, 2176, 2754, 3400, 4114, 4896, 5746, 6664, 7650, 8704, 9826, 11016, 12274, 13600, 14994, 16456, 17986, 19584, 21250, 22984, 24786, 26656, 28594, 30600, 32674, 34816, 37026, 39304, 41650, 44064, 46546, 49096, 51714, 54400, 57154, 59976, 62866, 65824, 68850, 71944
Offset: 0

Views

Author

Omar E. Pol, May 13 2018

Keywords

Comments

Sequence found by reading the line from 0, in the direction 0, 34, ..., in the square spiral whose vertices are the generalized 19-gonal numbers A303813.

Crossrefs

Cf. similar sequences of the type k*n^2: A000290 (k=1), A001105 (k=2), A033428 (k=3), A016742 (k=4), A033429 (k=5), A033581 (k=6), A033582 (k=7), A139098 (k=8), A016766 (k=9), A033583 (k=10), A033584 (k=11), A135453 (k=12), A152742 (k=13), A144555 (k=14), A064761 (k=15), A016802 (k=16), A244630 (k=17), A195321 (k=18), A244631 (k=19), A195322 (k=20), A064762 (k=21), A195323 (k=22), A244632 (k=23), A195824 (k=24), A016850 (k=25), A244633 (k=26), A244634 (k=27), A064763 (k=28), A244635 (k=29), A244636 (k=30), A244082 (k=32), this sequence (k=34), A016910 (k=36), A016982 (k=49), A017066 (k=64), A017162 (k=81), A017270 (k=100), A017390 (k=121), A017522 (k=144).

Programs

  • Magma
    [34*n^2: n in [0..50]]; // Vincenzo Librandi Jun 07 2018
  • Mathematica
    Table[34 n^2, {n, 0, 40}]
    LinearRecurrence[{3,-3,1},{0,34,136},50] (* Harvey P. Dale, Jul 23 2018 *)
  • PARI
    a(n) = 34*n^2;
    
  • PARI
    concat(0, Vec(34*x*(1 + x) / (1 - x)^3 + O(x^40))) \\ Colin Barker, Jun 12 2018
    

Formula

a(n) = 34*A000290(n) = 17*A001105(n) = 2*A244630(n).
G.f.: 34*x*(1 + x)/(1 - x)^3. - Vincenzo Librandi, Jun 07 2018
From Elmo R. Oliveira, Dec 02 2024: (Start)
E.g.f.: 34*x*(1 + x)*exp(x).
a(n) = A005843(n)*A008599(n).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2. (End)

A346904 Numbers with sum of digits equaling 17, divisible by 17, and containing the string "17".

Original entry on oeis.org

13175, 15317, 17153, 17306, 17612, 21743, 30617, 41174, 51731, 61217, 101762, 107117, 110177, 111707, 117062, 117215, 117521, 122417, 125171, 131750, 153017, 153170, 170153, 170306, 170612, 171071, 171224, 171530, 172142, 172601, 173060, 173213, 174131, 175202, 176120, 214217
Offset: 1

Views

Author

Tanya Khovanova, Aug 06 2021

Keywords

Examples

			13175 contains 17 as a substring; the sum of digits of 13175 is 17, and 13175 is divisible by 17. Thus, 13175 is in this sequence.
		

Crossrefs

Cf. A121669 (for 19 instead of 17).
Intersection of A008599, A166370, and A293877

Programs

  • Mathematica
    d17Q[n_] := Module[{idn = IntegerDigits[n]}, Total[idn] == 17 && MemberQ[Partition[idn, 2, 1], {1, 7}]]; Select[17*Range[20000], d17Q]
  • Python
    def ok(n): s = str(n); return n%17==0 and '17' in s and sum(map(int, s))==17
    print(list(filter(ok, range(214218)))) # Michael S. Branicky, Aug 06 2021

A144604 Christoffel word of slope 6/11.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Jan 13 2009

Keywords

Comments

The path is on the slope after 0, 17, 34, 51, 68, 85,... steps (see A008599), which gives the C-finite recurrence. - R. J. Mathar, May 28 2025

Crossrefs

See A144595 for further details.

Formula

a(n) = a(n-17). - R. J. Mathar, May 28 2025
G.f.: -x^2*(x^2+1)*(x^12+x^7-x^5+x^4+x^3-x^2+1)/ (x-1) /(1 +x +x^2 +x^3 +x^4 +x^5 +x^6 +x^7 +x^8 +x^9 +x^10 +x^11 +x^12 +x^13 +x^14 +x^15 +x^16) . - R. J. Mathar, May 28 2025
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