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 11-20 of 31 results. Next

A269100 a(n) = 13*n + 11.

Original entry on oeis.org

11, 24, 37, 50, 63, 76, 89, 102, 115, 128, 141, 154, 167, 180, 193, 206, 219, 232, 245, 258, 271, 284, 297, 310, 323, 336, 349, 362, 375, 388, 401, 414, 427, 440, 453, 466, 479, 492, 505, 518, 531, 544, 557, 570, 583, 596, 609, 622, 635, 648, 661, 674, 687, 700, 713, 726, 739
Offset: 0

Views

Author

Bruno Berselli, Feb 19 2016

Keywords

Comments

Any square mod 13 is one of 0, 1, 3, 4, 9, 10 or 12 (A010376) but not 11, and for this reason there are no squares in the sequence. Likewise, any cube mod 13 is one of 0, 1, 5, 8 or 12, therefore no a(k) is a cube.
Sequences of the type 13*n + k, for k = 0..12, without squares and cubes:
k = 2: A153080,
k = 6: A186113,
k = 7: A269044,
k = 11: this case.
The sum of the sixth powers of any two terms of the sequence is also a term of the sequence. Example: a(3)^6 + a(8)^6 = a(179129674278) = 2328685765625.
The primes of the sequence are listed in A140373.

Crossrefs

Subsequence of A094784, A106389.
Cf. A140373.
Similar sequences of the type k*n+k-2: A023443 (k=1), A005843 (k=2), A016777 (k=3), A016825 (k=4), A016885 (k=5), A016957 (k=6), A017041 (k=7), A017137 (k=8), A017245 (k=9), A017365 (k=10), A017497 (k=11), A017641 (k=12).
Sequences of the form 13*n+q: A008595 (q=0), A190991 (q=1), A153080 (q=2), A127547 (q=4), A154609 (q=5), A186113 (q=6), A269044 (q=7), this sequence (q=11).

Programs

  • Magma
    [13*n+11: n in [0..60]];
  • Mathematica
    13 Range[0,60] + 11
    Range[11, 800, 13]
    Table[13 n + 11, {n, 0, 60}] (* Bruno Berselli, Feb 22 2016 *)
    LinearRecurrence[{2,-1},{11,24},60] (* Harvey P. Dale, Jun 14 2023 *)
  • Maxima
    makelist(13*n+11, n, 0, 60);
    
  • PARI
    vector(60, n, n--; 13*n+11)
    
  • Python
    [13*n+11 for n in range(61)]
    
  • Sage
    [13*n+11 for n in range(61)]
    

Formula

G.f.: (11 + 2*x)/(1 - x)^2.
a(n) = -A153080(-n-1).
Sum_{i = h..h+13*k} a(i) = a(h*(13*k + 1) + k*(169*k + 35)/2).
Sum_{i >= 0} 1/a(i)^2 = .012486605016510955990... = polygamma(1, 11/13)/13^2.
E.g.f.: (11 + 13*x)*exp(x). - G. C. Greubel, May 31 2024

A125199 Triangle read by rows: T(n,k) = 4*n*k - n - k, 1<=k<=n.

Original entry on oeis.org

2, 5, 12, 8, 19, 30, 11, 26, 41, 56, 14, 33, 52, 71, 90, 17, 40, 63, 86, 109, 132, 20, 47, 74, 101, 128, 155, 182, 23, 54, 85, 116, 147, 178, 209, 240, 26, 61, 96, 131, 166, 201, 236, 271, 306, 29, 68, 107, 146, 185, 224, 263, 302, 341, 380, 32, 75, 118, 161, 204, 247
Offset: 1

Views

Author

Reinhard Zumkeller, Nov 24 2006

Keywords

Comments

A124934 gives the range: for n,k with 1<=k<=n exists at least one m such that A124934(m)=T(n,k);
row sums give A125200; central terms give A125201;
T(n,1) = A016789(n-1);
T(n,2) = A017041(n-1) for n>1;
T(n,3) = A017485(n-1) for n>2;
T(n,n-1) = A125202(n) for n>1;
T(n,n) = A002939(n).

Programs

  • Mathematica
    Flatten[Table[4*n*k-n-k,{n,15},{k,n}]] (* Harvey P. Dale, Nov 15 2014 *)

A047382 Numbers that are congruent to {0, 5} mod 7.

Original entry on oeis.org

0, 5, 7, 12, 14, 19, 21, 26, 28, 33, 35, 40, 42, 47, 49, 54, 56, 61, 63, 68, 70, 75, 77, 82, 84, 89, 91, 96, 98, 103, 105, 110, 112, 117, 119, 124, 126, 131, 133, 138, 140, 145, 147, 152, 154, 159, 161, 166, 168
Offset: 1

Views

Author

Keywords

Comments

Except for the first term, numbers m such that 36*m^2 + 72*m + 35 = (6*m+5)*(6*m+7) is not of the form p*(p+2), with p prime. - Vincenzo Librandi, Aug 05 2010
Nonnegative k such that k or 4*k + 1 is divisible by 7. - Bruno Berselli, Feb 13 2018

Crossrefs

Programs

  • Magma
    &cat[[7*n,7*n+5]: n in [0..23]];  // Bruno Berselli, Oct 17 2011
    
  • Mathematica
    {#, 5 + #} &/@ (7 Range[0, 30]) // Flatten (* or *) LinearRecurrence[{1, 1, -1}, {0, 5, 7}, 60] (* Harvey P. Dale, Dec 01 2016 *)
  • PARI
    a(n) = (14*n + 3*(-1)^n - 11)/4 \\ David Lovler, Sep 11 2022

Formula

a(n) = 7*n - a(n-1) - 9 for n>1, with a(1)=0. - Vincenzo Librandi, Aug 05 2010
a(n+1) = Sum_{k>=0} A030308(n,k)*b(k) with b(0)=5 and b(k)=A005009(k-1)=7*2^(k-1) for k>0. - Philippe Deléham, Oct 17 2011
From Bruno Berselli, Oct 17 2011: (Start)
G.f.: x^2*(5 + 2*x)/((1 + x)*(1 - x)^2).
a(n) = (14*n + 3*(-1)^n - 11)/4.
a(-n) = -A047352(n+2). (End)
a(n) = ceiling((7/3)*ceiling(3*n/2)). - Clark Kimberling, Jul 04 2012
E.g.f.: 2 + ((14*x - 11)*exp(x) + 3*exp(-x))/4. - David Lovler, Sep 11 2022

A126980 a(n) = 14*n + 47.

Original entry on oeis.org

47, 61, 75, 89, 103, 117, 131, 145, 159, 173, 187, 201, 215, 229, 243, 257, 271, 285, 299, 313, 327, 341, 355, 369, 383, 397, 411, 425, 439, 453, 467, 481, 495, 509, 523, 537, 551, 565, 579, 593, 607, 621, 635, 649, 663, 677, 691, 705, 719, 733, 747
Offset: 0

Views

Author

Robert H Barbour, Mar 20 2007, Jun 12 2007

Keywords

Comments

Superhighway created by 'LQTL Ant' L90R135L90R135 from iteration 47 where the Ant moves in a 'Moore neighborhood' (nine cells), the L indicates a left turn, the R a right turn, and the numerical value is the turn angle (in degrees) at each iteration.

References

  • P. Sakar, "A Brief History of Cellular Automata," ACM Computing Surveys, vol. 32, 2000.
  • S. Wolfram, A New Kind of Science, 1st ed. Il.: Wolfram Media Inc., 2002.

Crossrefs

Programs

Formula

From Chai Wah Wu, May 30 2016: (Start)
a(n) = 2*a(n-1) - a(n-2) for n > 1.
G.f.: (-33*x + 47)/(x - 1)^2. (End)
E.g.f.: (47 + 14*x)*exp(x). - G. C. Greubel, May 30 2016

Extensions

More terms from Stefan Steinerberger and Diana L. Mecum, Jun 17 2007

A155546 Triangle read by rows where T(m,n)=2mn + m + n - 5, 1<=n<=m.

Original entry on oeis.org

-1, 2, 7, 5, 12, 19, 8, 17, 26, 35, 11, 22, 33, 44, 55, 14, 27, 40, 53, 66, 79, 17, 32, 47, 62, 77, 92, 107, 20, 37, 54, 71, 88, 105, 122, 139, 23, 42, 61, 80, 99, 118, 137, 156, 175, 26, 47, 68, 89, 110, 131, 152, 173, 194, 215, 29, 52, 75, 98, 121, 144, 167, 190, 213
Offset: 1

Views

Author

Vincenzo Librandi, Jan 24 2009

Keywords

Comments

2*T(m,n)+11 = (2*m+1)*(2*n+1) is not prime.
First column: A016789, second column: A016873, third column: A017041, fourth column: A017257. - Vincenzo Librandi, Nov 21 2012

Examples

			Triangle begins:
-1;
2,  7;
5,  12, 19;
8,  17, 26, 35;
11, 22, 33, 44, 55;
14, 27, 40, 53, 66,  79;
17, 32, 47, 62, 77,  92,  107;
20, 37, 54, 71, 88,  105, 122, 139;
23, 42, 61, 80, 99,  118, 137, 156, 175;
26, 47, 68, 89, 110, 131, 152, 173, 194, 215; etc.
		

Crossrefs

Programs

  • Magma
    [2*n*k + n + k - 5: k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 21 2012
  • Mathematica
    t[n_,k_]:= 2 n*k + n + k - 5; Table[t[n, k], {n, 15}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 21 2012 *)

A163674 Triangle T(n,m) = 2*m*n + m + n + 9 read by rows.

Original entry on oeis.org

13, 16, 21, 19, 26, 33, 22, 31, 40, 49, 25, 36, 47, 58, 69, 28, 41, 54, 67, 80, 93, 31, 46, 61, 76, 91, 106, 121, 34, 51, 68, 85, 102, 119, 136, 153, 37, 56, 75, 94, 113, 132, 151, 170, 189, 40, 61, 82, 103, 124, 145, 166, 187, 208, 229, 43, 66, 89, 112, 135, 158, 181
Offset: 1

Views

Author

Vincenzo Librandi, Aug 03 2009

Keywords

Comments

2*T(m,n) - 17 =(2*n+1)*(2*m+1) and 2*T(n,n) - 17 is a square. Also:
first column: A112414;
second column: A016861;
third column: A017041;
fourth column: A017209. [Vincenzo Librandi, Nov 20 2012]

Examples

			Triangle begins:
  13;
  16,  21;
  19,  26,  33;
  22,  31,  40,  49;
  25,  36,  47,  58,  69;
  28,  41,  54,  67,  80,  93;
  31,  46,  61,  76,  91, 106, 121;
  34,  51,  68,  85, 102, 119, 136, 153;
		

Crossrefs

Programs

  • Magma
    [2*n*k + n + k + 9: k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 20 2012
    
  • Mathematica
    t[n_,k_]:=2 n*k + n + k + 9; Table[t[n, k], {n, 15}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 20 2012 *)
  • PARI
    for(n=1,10, for(m=1,n, print1(2*m*n + m + n + 9, ", "))) \\ G. C. Greubel, Aug 02 2017

Formula

T(n,m) = A163657(n,m) + 1.

Extensions

Edited by R. J. Mathar, Oct 12 2009

A155705 Triangle read by rows where T(m,n) = 2*m*n + m + n + 2.

Original entry on oeis.org

6, 9, 14, 12, 19, 26, 15, 24, 33, 42, 18, 29, 40, 51, 62, 21, 34, 47, 60, 73, 86, 24, 39, 54, 69, 84, 99, 114, 27, 44, 61, 78, 95, 112, 129, 146, 30, 49, 68, 87, 106, 125, 144, 163, 182, 33, 54, 75, 96, 117, 138, 159, 180, 201, 222, 36, 59, 82, 105, 128, 151
Offset: 1

Views

Author

Vincenzo Librandi, Jan 25 2009

Keywords

Comments

2*T(m,n)-3 = (2*m+1)*(2*n+1) is not prime, obviously. Also: first column: 3*A020725; second column: A016897; third column: A017041; fourth column: 3*A016789. - Vincenzo Librandi, Nov 20 2012

Examples

			Triangle begins:
6;
9,  14;
12, 19, 26;
15, 24, 33, 42;
18, 29, 40, 51, 62;
21, 34, 47, 60, 73,  86;
24, 39, 54, 69, 84,  99,  114;
27, 44, 61, 78, 95,  112, 129, 146;
30, 49, 68, 87, 106, 125, 144, 163, 182;
33, 54, 75, 96, 117, 138, 159, 180, 201, 222; etc.
		

Crossrefs

Programs

  • Magma
    [2*n*k + n + k + 2: k in [1..n],  n in [1..11]]; // Vincenzo Librandi, Nov 20 2012
  • Mathematica
    t[n_,k_]:=2 n*k + n + k + 2; Table[t[n, k], {n, 11}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 20 2012 *)

A182719 Numbers of the form 5k + 4, 7k + 5, or 11k + 6.

Original entry on oeis.org

4, 5, 6, 9, 12, 14, 17, 19, 24, 26, 28, 29, 33, 34, 39, 40, 44, 47, 49, 50, 54, 59, 61, 64, 68, 69, 72, 74, 75, 79, 82, 83, 84, 89, 94, 96, 99, 103, 104, 105, 109, 110, 114, 116, 117, 119, 124, 127, 129, 131, 134, 138, 139, 144, 145, 149, 152, 154, 159, 160, 164
Offset: 1

Views

Author

Omar E. Pol, Feb 08 2011

Keywords

Comments

Numbers such that the Ramanujan congruences apply, making p(a(n)) divisible by at least one of 5, 7, or 11, where p is A000041.
Union of A016897, A017041 and A017461.
First differences are periodic with period length 145.

Crossrefs

Programs

  • Magma
    IsA182719:=func< n | exists{ k: k in [0..n div 5] | n in [5*k+4, 7*k+5, 11*k+6] } >; [ n: n in [1..160] | IsA182719(n) ]; // Klaus Brockhaus, Feb 08 2011
  • Mathematica
    Union[With[{no=30},Join[5Range[0,no]+4,7Range[0,no]+5,11Range[0,no]+6]]]  (* Harvey P. Dale, Feb 18 2011 *)

Formula

a(n) = a(n-145) + 385 = a(n-1) + a(n-145) - a(n-146).

Extensions

Rewritten by Charles R Greathouse IV and Klaus Brockhaus, Feb 08 2011

A220502 spt(7n+5) where spt(n) = A092269(n).

Original entry on oeis.org

14, 238, 1820, 10486, 48692, 196168, 706671, 2335760, 7185780, 20832168, 57385734, 151261320, 383516700, 939524019, 2231714982, 5155845968, 11614187984, 25565740130, 55096236664, 116437751108, 241655216355, 493152387294, 990688365380
Offset: 0

Views

Author

Omar E. Pol, Jan 18 2013

Keywords

Comments

a(n) is divisible by 7 (see A220507).

Crossrefs

Formula

a(n) = A092269(A017041(n)).

A220507 a(n) = spt(7n+5)/7 where spt(n) = A092269(n).

Original entry on oeis.org

2, 34, 260, 1498, 6956, 28024, 100953, 333680, 1026540, 2976024, 8197962, 21608760, 54788100, 134217717, 318816426, 736549424, 1659169712, 3652248590, 7870890952, 16633964444, 34522173765, 70450341042, 141526909340, 280158178412
Offset: 0

Views

Author

Omar E. Pol, Jan 18 2013

Keywords

Comments

That spt(7n+5) == 0 (mod 7) is one of the congruences stated by George E. Andrews. See theorem 2 in the Andrews' paper. See also A220505 and A220513.

Crossrefs

Programs

  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0 || i==1, n, {q, r} = QuotientRemainder[n, i]; If[r == 0, q, 0] + Sum[b[n - i*j, i - 1], {j, 0, n/i}]];
    spt[n_] := b[n, n];
    a[n_] := spt[7 n + 5]/7;
    Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Jan 30 2019, after Alois P. Heinz in A092269 *)

Formula

a(n) = A092269(A017041(n))/7 = A220502(n)/7.
Previous Showing 11-20 of 31 results. Next