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 21-30 of 37 results. Next

A004769 Numbers whose binary expansion ends in 011.

Original entry on oeis.org

11, 19, 27, 35, 43, 51, 59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171, 179, 187, 195, 203, 211, 219, 227, 235, 243, 251, 259, 267, 275, 283, 291, 299, 307, 315, 323, 331, 339, 347, 355, 363, 371, 379, 387, 395, 403, 411, 419, 427, 435, 443, 451, 459, 467, 475, 483, 491
Offset: 0

Views

Author

Keywords

Crossrefs

Essentially same as A017101.

Programs

  • Magma
    [8*n+11: n in [0..60]]; // Vincenzo Librandi, Jul 12 2011
    
  • Mathematica
    Table[8*n+11, {n,0,60}] (* G. C. Greubel, Oct 13 2018 *)
    LinearRecurrence[{2,-1},{11,19},80] (* Harvey P. Dale, Aug 09 2023 *)
    Select[Range[10,500],Take[IntegerDigits[#,2],-3]=={0,1,1}&] (* or *) Rest[FromDigits[#,2]&/@(Join[#,{0,1,1}]&/@Tuples[{0,1},6])] (* Harvey P. Dale, Mar 23 2025 *)
  • PARI
    a(n)=8*n+11 \\ Charles R Greathouse IV, Jul 11 2016

Formula

a(n) = 8*n + 11. - Vincenzo Librandi, Jul 12 2011
From G. C. Greubel, Oct 13 2018: (Start)
a(n) = 2*a(n-1) - a(n-2).
G.f.: (11 - 3*x)/(1-x)^2.
E.g.f.: (8*x + 11)*exp(x). (End)

A047458 Numbers that are congruent to {0, 3, 4} mod 8.

Original entry on oeis.org

0, 3, 4, 8, 11, 12, 16, 19, 20, 24, 27, 28, 32, 35, 36, 40, 43, 44, 48, 51, 52, 56, 59, 60, 64, 67, 68, 72, 75, 76, 80, 83, 84, 88, 91, 92, 96, 99, 100, 104, 107, 108, 112, 115, 116, 120, 123, 124, 128, 131, 132, 136, 139, 140, 144, 147, 148, 152, 155, 156
Offset: 1

Views

Author

Keywords

Crossrefs

Union of A008586 and A017101. - Michel Marcus, Jun 01 2017

Programs

  • Magma
    [n : n in [0..150] | n mod 8 in [0, 3, 4]]; // Wesley Ivan Hurt, Jun 09 2016
  • Maple
    A047458:=n->8*n/3-3-cos(2*n*Pi/3)-sin(2*n*Pi/3)/(3*sqrt(3)): seq(A047458(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016
  • Mathematica
    Select[Range[0, 150], MemberQ[{0, 3, 4}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)
    LinearRecurrence[{1,0,1,-1},{0,3,4,8},90] (* Harvey P. Dale, May 31 2017 *)

Formula

G.f.: x^2*(3+x+4*x^2)/((1-x)^2*(1+x+x^2)). [Colin Barker, May 13 2012]
From Wesley Ivan Hurt, Jun 09 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = 8*n/3-3-cos(2*n*Pi/3)-sin(2*n*Pi/3)/(3*sqrt(3)).
a(3k) = 8k-4, a(3k-1) = 8k-5, a(3k-2) = 8k-8. (End)

A078688 Continued fraction expansion of e^(1/4).

Original entry on oeis.org

1, 3, 1, 1, 11, 1, 1, 19, 1, 1, 27, 1, 1, 35, 1, 1, 43, 1, 1, 51, 1, 1, 59, 1, 1, 67, 1, 1, 75, 1, 1, 83, 1, 1, 91, 1, 1, 99, 1, 1, 107, 1, 1, 115, 1, 1, 123, 1, 1, 131, 1, 1, 139, 1, 1, 147, 1, 1, 155, 1, 1, 163, 1, 1, 171, 1, 1, 179, 1, 1, 187
Offset: 0

Views

Author

Benoit Cloitre, Dec 17 2002

Keywords

Crossrefs

Programs

  • Mathematica
    ContinuedFraction[E^(1/4),80] (* Harvey P. Dale, Nov 19 2011 *)

Formula

a(4k+2) = 8k+3, otherwise a(i) = 1.
G.f.: (6x^4+2x)/(1-x^3)^2+1/(1-x). - Ralf Stephan, Mar 13 2003

A168378 a(n) = 3 + 8*floor(n/2).

Original entry on oeis.org

3, 11, 11, 19, 19, 27, 27, 35, 35, 43, 43, 51, 51, 59, 59, 67, 67, 75, 75, 83, 83, 91, 91, 99, 99, 107, 107, 115, 115, 123, 123, 131, 131, 139, 139, 147, 147, 155, 155, 163, 163, 171, 171, 179, 179, 187, 187, 195, 195, 203, 203, 211, 211, 219, 219, 227, 227, 235, 235
Offset: 1

Views

Author

Vincenzo Librandi, Nov 24 2009

Keywords

Comments

More generally, the sequences generated by the recursive relation b(n) = h*n - b(n-1) + k, with b(1)=c and h, k, c, prefixed integers, have the closed form b(n) = (2*h*n + (3*h + 2*k - 4*c)*(-1)^n + h + 2*k)/4. Also, if 2*c = h+k, then b(n) = c + h*floor(n/2); if 2*c = 2*h+k, then b(n) = c + h*floor((n-1)/2); if 2*c = k, b(n) = c + h*floor((n+1)/2). - Bruno Berselli, Sep 18 2013

Crossrefs

Programs

  • Magma
    [3+8*Floor(n/2): n in [1..70]]; // Vincenzo Librandi, Sep 18 2013
  • Mathematica
    Table[ 3 + 8*floor(n/2), {n,60}] (* Bruno Berselli, Sep 18 2013 *)
    CoefficientList[Series[(3 + 8 x - 3 x^2)/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 18 2013 *)
    LinearRecurrence[{1,1,-1},{3,11,11},80] (* Harvey P. Dale, Oct 05 2022 *)

Formula

a(n) = 8*n - a(n-1) - 2, with n>1, a(1)=3.
G.f.: x*(3 + 8*x - 3*x^2)/((1+x)*(x-1)^2). - Vincenzo Librandi, Sep 18 2013
a(n) = a(n-1) +a(n-2) -a(n-3). - Vincenzo Librandi, Sep 18 2013
a(n) = 4*n + 2*(-1)^n + 1. - Bruno Berselli, Sep 18 2013
a(n) = A168381(n) + 1 = A168398(n) - 1. - Bruno Berselli, Sep 18 2013
E.g.f.: (4*x + 3)*cosh(x) + (4*x - 1)*sinh(x) - 3. - G. C. Greubel, Jul 19 2016

Extensions

New definition by Vincenzo Librandi, Sep 18 2013

A177065 a(n) = (8*n+3)*(8*n+5).

Original entry on oeis.org

15, 143, 399, 783, 1295, 1935, 2703, 3599, 4623, 5775, 7055, 8463, 9999, 11663, 13455, 15375, 17423, 19599, 21903, 24335, 26895, 29583, 32399, 35343, 38415, 41615, 44943, 48399, 51983, 55695, 59535, 63503, 67599, 71823, 76175, 80655, 85263, 89999, 94863, 99855
Offset: 0

Views

Author

Vincenzo Librandi, May 31 2010

Keywords

Comments

Cf. comment of Reinhard Zumkeller in A177059: in general, (h*n+h-k)*(h*n+k) = h^2*A002061(n+1) + (h-k)*k - h^2; therefore a(n) = 64*A002061(n+1) - 49. - Bruno Berselli, Aug 24 2010

Crossrefs

Programs

Formula

a(n) = 128*n + a(n-1) with n > 0, a(0)=15.
a(n) = A125169(A016754(n) - 1). - Reinhard Zumkeller, Jul 05 2010
a(0)=15, a(1)=143, a(2)=399, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Harvey P. Dale, Mar 13 2013
G.f.: (15+98*x+15*x^2)/(1-x)^3. - Vincenzo Librandi, Apr 08 2013
From Amiram Eldar, Feb 19 2023: (Start)
a(n) = A017101(n)*A004770(n).
Sum_{n>=0} 1/a(n) = (sqrt(2)-1)*Pi/16.
Sum_{n>=0} (-1)^n/a(n) = (cos(Pi/8) * log(tan(3*Pi/16)) + sin(Pi/8) * log(cot(Pi/16)))/4.
Product_{n>=0} (1 - 1/a(n)) = sec(Pi/8)*cos(Pi/(4*sqrt(2))).
Product_{n>=0} (1 + 1/a(n)) = sec(Pi/8). (End)
E.g.f.: exp(x)*(15 + 64*x*(2 + x)). - Elmo R. Oliveira, Oct 25 2024

Extensions

Edited by N. J. A. Sloane, Jun 22 2010

A234011 The sums of 2 consecutive odious numbers (A000069).

Original entry on oeis.org

3, 6, 11, 15, 19, 24, 27, 30, 35, 40, 43, 47, 51, 54, 59, 63, 67, 72, 75, 79, 83, 86, 91, 96, 99, 102, 107, 111, 115, 120, 123, 126, 131, 136, 139, 143, 147, 150, 155, 160, 163, 166, 171, 175, 179, 184, 187, 191, 195, 198, 203, 207, 211, 216, 219, 222, 227, 232, 235, 239, 243, 246
Offset: 1

Views

Author

Gerasimov Sergey, Dec 27 2013

Keywords

Comments

The union of A131323(k) and (A225822(m)+(-1)^m).
All even numbers in this sequence are evil numbers (A001969).
It seems that A233388(n) = a(A091785(n)).

Crossrefs

Cf. A000069, A003159 (indices of odd numbers in A234011), A036554 (indices of even numbers in A234011), A131323 (odd sums of 2 successive odious or 2 successive evil numbers), A233388 (odious numbers in A234011), A234431 (sums of 2 consecutive evil numbers), A017101, A091785, A225822, A227930, A233388.

Programs

Formula

a(n) = A000069(n) + A000069(n + 1).
4n - 2 <= a(n) <= 4n. - Charles R Greathouse IV, Dec 29 2013
a(2n+1) = 8n + 3 = A017101(n). - Ralf Stephan, Dec 31 2013

Extensions

Terms recomputed and checked by Antti Karttunen, Dec 29 2013

A354938 Row 8 of A354940: Numbers k for which A345992(k) = 8, divided by 8.

Original entry on oeis.org

3, 9, 11, 17, 19, 25, 27, 33, 41, 43, 49, 57, 59, 67, 73, 81, 83, 89, 97, 105, 107, 113, 121, 129, 131, 137, 139, 145, 161, 163, 169, 177, 179, 185, 193, 201, 209, 211, 217, 225, 227, 233, 241, 243, 249, 251, 257, 281, 283, 289, 297, 305, 307, 313, 321, 329, 331, 337, 345, 347, 353, 361, 377, 379, 393, 401, 409, 417
Offset: 1

Views

Author

Antti Karttunen, Jun 15 2022

Keywords

Comments

Apparently, all terms are either of the form 8k+1 (in A017077) or 8k+3 (in A017101).

Crossrefs

Programs

  • Mathematica
    q[n_] := Module[{m = 1}, While[!Divisible[m*(m + 1), 8*n], m++]; GCD[8*n, m] == 8]; Select[Range[420], q] (* Amiram Eldar, Jun 17 2022 *)
  • PARI
    A354938(n) = A354940sq(8,n);

A047400 Numbers that are congruent to {1, 3, 6} mod 8.

Original entry on oeis.org

1, 3, 6, 9, 11, 14, 17, 19, 22, 25, 27, 30, 33, 35, 38, 41, 43, 46, 49, 51, 54, 57, 59, 62, 65, 67, 70, 73, 75, 78, 81, 83, 86, 89, 91, 94, 97, 99, 102, 105, 107, 110, 113, 115, 118, 121, 123, 126, 129, 131, 134, 137, 139, 142, 145, 147, 150, 153, 155, 158
Offset: 1

Views

Author

Keywords

Comments

Union of A017077, A017101 and A017137. - R. J. Mathar, Apr 14 2008

Crossrefs

Programs

  • Magma
    [n: n in [1..300] | n mod 8 in [1, 3, 6]]; // Vincenzo Librandi, Mar 27 2011
  • Maple
    A047400:=n->2*(12*n-9+sqrt(3)*sin(2*n*Pi/3))/9: seq(A047400(n), n=1..100); # Wesley Ivan Hurt, Jun 10 2016
  • Mathematica
    Select[Range[0, 150], MemberQ[{1, 3, 6}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 10 2016 *)
  • PARI
    a(n) = {x=8*floor((n-1)/3);if(n%3==1,x=x+1);if(n%3==2,x=x+3);if(n%3==0,x=x+6);x} \\ Michael B. Porter, Oct 02 2009
    

Formula

a(n) = A004773(n-1) + A004773(n). - Gary W. Adamson, Sep 13 2007
G.f.: x*(1+x)*(2x^2+x+1)/((-1+x)^2*(x^2+x+1)). a(n) = a(n-3)+8 for n>3. - R. J. Mathar, Apr 14 2008
From Wesley Ivan Hurt, Jun 10 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = 2*(12*n-9+sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-2, a(3k-1) = 8k-5, a(3k-2) = 8k-7. (End)

A047573 Numbers that are congruent to {0, 1, 2, 4, 5, 6, 7} mod 8.

Original entry on oeis.org

0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 80, 81
Offset: 1

Views

Author

Keywords

Comments

Complement of A017101. - Michel Marcus, Sep 13 2015

Crossrefs

Cf. A017101 (8n+3).

Programs

  • Magma
    [n+Floor((n-4)/7) : n in [1..100]]; // Wesley Ivan Hurt, Sep 12 2015
    
  • Magma
    I:=[0,1,2,4,5,6,7,8]; [n le 8 select I[n] else Self(n-1) + Self(n-7) - Self(n-8): n in [1..80]]; // Vincenzo Librandi, Sep 13 2015
    
  • Maple
    for n from 0 to 200 do if n mod 8 <> 3 then printf(`%d,`,n) fi: od:
  • Mathematica
    Table[n+Floor[(n-4)/7], {n, 100}] (* Wesley Ivan Hurt, Sep 12 2015 *)
    LinearRecurrence[{1, 0, 0, 0, 0, 0, 1, -1}, {0, 1, 2, 4, 5, 6, 7, 8}, 80] (* Vincenzo Librandi, Sep 13 2015 *)
    DeleteCases[Range[0,100],?(Mod[#,8]==3&)] (* _Harvey P. Dale, Oct 05 2020 *)
  • Python
    def A047573(n):
        a, b = divmod(n-1,7)
        return (0,1,2,4,5,6,7)[b]+(a<<3) # Chai Wah Wu, Jan 27 2023

Formula

G.f.: x^2*(x^6+x^5+x^4+x^3+2*x^2+x+1)/((x-1)^2*(x^6+x^5+x^4+x^3+x^2+x+1)). [Colin Barker, Jun 22 2012]
From Wesley Ivan Hurt, Sep 12 2015: (Start)
a(n) = a(n-1) + a(n-7) - a(n-8) for n>8.
a(n) = n + floor((n-4)/7). (End)
From Wesley Ivan Hurt, Jul 21 2016: (Start)
a(n) = a(n-7) + 8 for n>7.
a(n) = (56*n - 49 + (n mod 7) + ((n+1) mod 7) + ((n+2) mod 7) - 6*((n+3) mod 7) + ((n+4) mod 7) + ((n+5) mod 7) + ((n+6) mod 7))/49.
a(7*k) = 8*k-1, a(7*k-1) = 8*k-2, a(7*k-2) = 8*k-3, a(7*k-3) = 8*k-4, a(7*k-4) = 8*k-6, a(7*k-5) = 8*k-7, a(7*k-6) = 8*k-8. (End)

Extensions

More terms from James Sellers, Feb 19 2001

A137192 Lucky numbers (A000959) which are congruent to 3 mod 8.

Original entry on oeis.org

3, 43, 51, 67, 75, 99, 115, 163, 171, 195, 211, 219, 235, 259, 267, 283, 307, 331, 339, 427, 451, 475, 483, 579, 619, 643, 651, 699, 723, 739, 787, 819, 867, 883, 931, 979, 1011, 1107, 1123, 1147, 1155, 1179, 1203, 1219, 1251, 1275, 1291, 1323, 1339, 1387, 1395, 1419
Offset: 1

Views

Author

N. J. A. Sloane, Mar 07 2008

Keywords

Crossrefs

Intersection of A000959 and A017101.
Previous Showing 21-30 of 37 results. Next