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 1-8 of 8 results.

A235499 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(3).

Original entry on oeis.org

0, 1, 2, 3, 9, 10, 11, 12, 13, 19, 20, 21, 22, 23, 29, 30, 31, 32, 33, 39, 40, 41, 42, 43, 49, 50, 51, 52, 53, 59, 60, 61, 62, 63, 69, 70, 71, 72, 73, 79, 80, 81, 82, 83, 89, 90, 91, 92, 93, 99, 100, 101, 102, 103, 109, 110, 111, 112, 113, 119, 120, 121, 122, 123, 129
Offset: 0

Views

Author

Vincenzo Librandi, Feb 06 2014

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(x^5 + 6 x^4 + x^3 + x^2 + x)/(x^6 - x^5 - x + 1), {x, 0, 50}], x] (* Vincenzo Librandi, Feb 08 2014 *)
    nxt[n_]:=If[Mod[n,10]==3,FromDigits[Join[Most[IntegerDigits[n]],{9}]], n+ 1]; NestList[nxt,0,70] (* or *) LinearRecurrence[{1,0,0,0,1,-1},{0,1,2,3,9,10},70] (* Harvey P. Dale, Oct 02 2016 *)

Formula

G.f.: (x^5+6*x^4+x^3+x^2+x)/(x^6-x^5-x+1). - Alois P. Heinz, Feb 07 2014

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

A237341 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(4).

Original entry on oeis.org

0, 1, 2, 3, 4, 16, 17, 18, 19, 20, 21, 22, 23, 24, 216, 217, 218, 219, 220, 221, 222, 223, 224, 2216, 2217, 2218, 2219, 2220, 2221, 2222, 2223, 2224, 22216, 22217, 22218, 22219, 22220, 22221, 22222, 22223, 22224, 222216, 222217, 222218, 222219, 222220, 222221
Offset: 0

Views

Author

Vincenzo Librandi, Feb 06 2014

Keywords

Crossrefs

Formula

G.f.: (10*x^17 +20*x^16 +30*x^15 +40*x^14 -20*x^13 -10*x^12 +10*x^10 +20*x^9 +19*x^8 +18*x^7 +17*x^6 +16*x^5 +4*x^4 +3*x^3 +2*x^2 +x)/(10*x^18 -11*x^9 +1). - Alois P. Heinz, Feb 07 2014

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

A235498 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(2).

Original entry on oeis.org

0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59, 60, 61, 62, 64, 65, 66, 67, 68, 69, 70, 71, 72, 74
Offset: 0

Views

Author

Vincenzo Librandi, Feb 06 2014

Keywords

Comments

An alternative and simpler definition: numbers not ending in 3. - Charles R Greathouse IV, Feb 07 2014

Crossrefs

Subsequence of A052405.

Formula

G.f.: (x^9 +x^8 +x^7 +x^6 +x^5 +x^4 +2*x^3 +x^2 +x) / (x^10 -x^9 -x +1). - Alois P. Heinz, Feb 07 2014

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

A237344 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(7).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 49, 50, 51, 52, 53, 54, 55, 56, 57, 549, 550, 551, 552, 553, 554, 555, 556, 557, 5549, 5550, 5551, 5552, 5553, 5554, 5555, 5556, 5557, 55549, 55550, 55551, 55552, 55553, 55554, 55555, 55556, 55557, 555549, 555550, 555551, 555552
Offset: 0

Views

Author

Vincenzo Librandi, Feb 06 2014

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(10 x^17 - 20 x^16 - 10 x^15 + 10 x^13 + 20 x^12 + 30 x^11 + 40 x^10 + 50 x^9 + 49 x^8 + 7 x^7 + 6 x^6 + 5 x^5 + 4 x^4 + 3 x^3 + 2 x^2 + x)/(10 x^18 -11 x^9 + 1), {x, 0, 50}], x] (* Vincenzo Librandi, Sep 24 2014 *)

Formula

G.f.: (10*x^17 -20*x^16 -10*x^15 +10*x^13 +20*x^12 +30*x^11 +40*x^10 +50*x^9 +49*x^8 +7*x^7 +6*x^6 +5*x^5 +4*x^4 +3*x^3 +2*x^2 +x)/(10*x^18 -11*x^9 +1). - Alois P. Heinz, Feb 07 2014

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

A237415 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^3. This is k(2).

Original entry on oeis.org

0, 1, 2, 8, 9, 10, 11, 12, 18, 19, 20, 21, 22, 28, 29, 30, 31, 32, 38, 39, 40, 41, 42, 48, 49, 50, 51, 52, 58, 59, 60, 61, 62, 68, 69, 70, 71, 72, 78, 79, 80, 81, 82, 88, 89, 90, 91, 92, 98, 99, 100, 101, 102, 108, 109, 110, 111, 112, 118, 119, 120, 121, 122, 128
Offset: 0

Views

Author

Vincenzo Librandi, Feb 07 2014

Keywords

Comments

Nonnegative integers m such that floor(2*m^2/10) = 2*floor(m^2/10). [Bruno Berselli, Dec 08 2015]

Crossrefs

Programs

  • Magma
    I:=[0,1,2,8,9,10]; [n le 6 select I[n] else Self(n-1)+Self(n-5)-Self(n-6): n in [1..80]]; // Vincenzo Librandi, Feb 12 2014
  • Mathematica
    LinearRecurrence[{1, 0, 0, 0, 1, -1}, {0, 1, 2, 8, 9, 10}, 70] (* Bruno Berselli, Feb 08 2014 *)
    CoefficientList[Series[x (1 + x + 6 x^2 + x^3 + x^4)/((1 - x)^2 (1 + x + x^2 + x^3 + x^4)), {x, 0, 100}], x] (* Vincenzo Librandi, Feb 12 2014 *)
    NestList[If[Mod[#,10]==2,FromDigits[Join[Most[IntegerDigits[#]],{8}]], #+ 1]&,0,100] (* Harvey P. Dale, Feb 21 2016 *)

Formula

G.f.: x*(1 + x + 6*x^2 + x^3 + x^4)/((1 - x)^2*(1 + x + x^2 + x^3 + x^4)). [Bruno Berselli, Feb 08 2014]
a(n) = a(n-1)+a(n-5)-a(n-6). - Vincenzo Librandi, Feb 12 2014

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

A237342 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(5).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 25, 225, 2225, 22225, 222225, 2222225, 22222225, 222222225, 2222222225, 22222222225, 222222222225, 2222222222225, 22222222222225, 222222222222225, 2222222222222225, 22222222222222225, 222222222222222225, 2222222222222222225
Offset: 0

Views

Author

Vincenzo Librandi, Feb 06 2014

Keywords

Crossrefs

Programs

  • Mathematica
    Join[Range[0, 4], Table[(25 + 2 10^(n - 4))/9, {n, 5, 30}]] (* Bruno Berselli, Feb 08 2014 *)

Formula

G.f.: (10*x^6-9*x^5-9*x^4-9*x^3-9*x^2+x)/(10*x^2-11*x+1). - Alois P. Heinz, Feb 07 2014
a(n) = ( 25 + 2*10^(n-4) )/9 for n>4. [Bruno Berselli, Feb 08 2014]

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

A237343 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(6).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 36, 336, 3336, 33336, 333336, 3333336, 33333336, 333333336, 3333333336, 33333333336, 333333333336, 3333333333336, 33333333333336, 333333333333336, 3333333333333336, 33333333333333336, 333333333333333336, 3333333333333333336
Offset: 0

Views

Author

Vincenzo Librandi, Feb 06 2014

Keywords

Crossrefs

Programs

  • Mathematica
    Join[Range[0, 5], Table[(8 + 10^(n - 5))/3, {n, 6, 30}]] (* Bruno Berselli, Feb 08 2014 *)

Formula

G.f.: (20*x^7-9*x^6-9*x^5-9*x^4-9*x^3-9*x^2+x)/(10*x^2-11*x+1). - Alois P. Heinz, Feb 07 2014
a(n) = ( 8 + 10^(n-5) )/3 for n>5. [Bruno Berselli, Feb 08 2014]

Extensions

Definition by N. J. A. Sloane, Feb 07 2014

A237345 For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(8).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 64, 65, 66, 67, 68, 664, 665, 666, 667, 668, 6664, 6665, 6666, 6667, 6668, 66664, 66665, 66666, 66667, 66668, 666664, 666665, 666666, 666667, 666668, 6666664, 6666665, 6666666, 6666667, 6666668, 66666664, 66666665, 66666666
Offset: 0

Views

Author

Vincenzo Librandi, Feb 06 2014

Keywords

Crossrefs

Formula

G.f.: -(10*x^13 +10*x^12 +10*x^11 +10*x^10 +20*x^9 -25*x^8 -15*x^7 -5*x^6 +5*x^5 +4*x^4 +3*x^3 +2*x^2+x)/(-10*x^10+11*x^5-1). - Alois P. Heinz, Feb 07 2014

Extensions

Definition by N. J. A. Sloane, Feb 07 2014
Showing 1-8 of 8 results.