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 1-4 of 4 results.

A077076 Trajectory of 537 under the Reverse and Add! operation carried out in base 2, written in base 10.

Original entry on oeis.org

537, 1146, 1899, 3618, 4713, 9522, 14427, 28386, 37533, 84966, 138123, 353004, 466209, 738024, 833301, 1525224, 1718853, 3048912, 3239469, 6196176, 6583437, 12389280, 12770397, 24975264, 25749789, 49944384, 50706621, 100282176
Offset: 0

Views

Author

Klaus Brockhaus, Oct 25 2002

Keywords

Comments

The base 2 trajectory of 537 = A075252(4) provably does not contain a palindrome. A proof can be based on the formula given below.
lim_{n -> infinity} a(n)/a(n-1) = 1 for n mod 2 = 1.
lim_{n -> infinity} a(n)/a(n-1) = 2 for n mod 2 = 0.
Interleaving of 3*A177682, 6*A177683, 3*A177684, 6*A177685.

Examples

			537 (decimal) = 1000011001 -> 1000011001 + 1001100001 = 10001111010= 1146 (decimal).
		

Crossrefs

Cf. A058042 (trajectory of 22 in base 2, written in base 2), A061561 (trajectory of 22 in base 2), A075253 (trajectory of 77 in base 2), A075268 (trajectory of 442 in base 2), A077077 (trajectory of 775 in base 2), A075252 (trajectory of n in base 2 does not reach a palindrome and (presumably) does not join the trajectory of any term m < n).
Cf. A177682 (a(4*n)/3), A177683 (a(4*n+1)/6), A177684 (a(4*n+2)/3), A177685 (a(4*n+3)/6).

Programs

  • Haskell
    a077076 n = a077076_list !! n
    a077076_list = iterate a055944 537  -- Reinhard Zumkeller, Apr 21 2013
  • Magma
    trajectory:=function(init, steps, base) a:=init; S:=[a]; for n in [1..steps] do a+:=Seqint(Reverse(Intseq(a,base)),base); Append(~S, a); end for; return S; end function; trajectory(537, 27, 2);
    
  • Mathematica
    NestWhileList[# + IntegerReverse[#, 2] &, 537,  # !=
    IntegerReverse[#, 2] &, 1, 27] (* Robert Price, Oct 18 2019 *)
  • PARI
    trajectory(n,steps) = {local(v, k=n); for(j=0, steps, print1(k, ", "); v=binary(k); k+=sum(j=1, #v, 2^(j-1)*v[j]))};
    trajectory(537,27);
    

Formula

a(0), ..., a(11) as above; for n > 11 and
n = 0 (mod 4): a(n) = 3*2^(2*k+13)+18249*2^k-3 where k = (n-4)/4;
n = 1 (mod 4): a(n) = 6*2^(2*k+13)-12102*2^k where k = (n-5)/4;
n = 2 (mod 4): a(n) = 6*2^(2*k+13)+11718*2^k-3 where k = (n-6)/4;
n = 3 (mod 4): a(n) = 12*2^(2*k+13)-11910*2^k where k = (n-7)/4.
G.f.: 3*(179+382*x+96*x^2+60*x^3-328*x^4-444*x^5+1170*x^6+2232*x^7 +1166*x^8+5644*x^9+15402*x^10+46922*x^11+39850*x^12-62920*x^13-132612*x^14 -97532*x^15-34148*x^16+83800*x^17+109224*x^18+21856*x^19) / ((1-x)*(1+x)*(1-2*x^2)*(1-2*x^4)).
G.f. for the sequence starting at a(12): 3*x^12*(155403+246008*x-188442*x^2-229616*x^3-260350*x^4-508920*x^5+293388*x^6+492528*x^7) / ((1-x)*(1+x)*(1-2*x^2)*(1-2*x^4))
a(n+1) = A055944(a(n)). - Reinhard Zumkeller, Apr 21 2013

Extensions

Comment edited and three comments added, g.f. edited, PARI program revised, MAGMA program and crossrefs added by Klaus Brockhaus, May 12 2010

A177682 a(n) = 6*a(n-1)-8*a(n-2)-3 for n > 4; a(0)=179, a(1)=1571, a(2)=12511, a(3)=155403, a(4)=572951.

Original entry on oeis.org

179, 1571, 12511, 155403, 572951, 2194479, 8583263, 33943743, 134996351, 538428159, 2150598143, 8596163583, 34372196351, 137463869439, 549805645823, 2199122919423, 8796292349951, 35184770744319, 140738285666303
Offset: 0

Views

Author

Klaus Brockhaus, May 12 2010

Keywords

Comments

Related to Reverse and Add trajectory of 537 in base 2: a(n) = A077076(4*n)/3, i.e. one third of first quadrisection of A077076.

Crossrefs

Cf. A077076 (Reverse and Add trajectory of 537 in base 2), A177683, A177684, A177685.

Programs

  • Magma
    [179, 1571, 12511] cat [2*4^(n+5)+6083*2^(n-1)-1: n in [3..25]]; // Vincenzo Librandi, Sep 24 2013
  • Mathematica
    Join[{179,1571,12511},LinearRecurrence[{7,-14,8},{155403,572951,2194479},20]] (* Harvey P. Dale, Oct 06 2011 *)
    CoefficientList[Series[(179 + 318 x + 4020 x^2 + 88388 x^3 - 352284 x^4 + 259376 x^5)/((1 - x) (1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)
  • PARI
    {m=19; v=concat([179, 1571, 12511, 155403, 572951], vector(m-5)); for(n=6 ,m, v[n]=6*v[n-1]-8*v[n-2]-3); v}
    

Formula

a(n) = 2*4^(n+5)+6083*2^(n-1)-1 for n > 2.
G.f.: (179+318*x+4020*x^2+88388*x^3-352284*x^4+259376*x^5) / ((1-x)*(1-2*x)*(1-4*x)).
G.f. for the sequence starting at a(3): x^3*(155403-514870*x+359464*x^2) / ((1-x)*(1-2*x)*(1-4*x)).

A177683 a(n) = 6*a(n-1)-8*a(n-2) for n > 4; a(0)=191, a(1)=1587, a(2)=14161, a(3)=123004, a(4)=508152.

Original entry on oeis.org

191, 1587, 14161, 123004, 508152, 2064880, 8324064, 33425344, 133959552, 536354560, 2146450944, 8587869184, 34355607552, 137430691840, 549739290624, 2198990209024, 8796026929152, 35184239902720, 140737223983104
Offset: 0

Views

Author

Klaus Brockhaus, May 12 2010

Keywords

Comments

Related to Reverse and Add trajectory of 537 in base 2: a(n) = A077076(4*n+1)/6, i.e., one sixth of second quadrisection of A077076.

Crossrefs

Cf. A077076 (Reverse and Add trajectory of 537 in base 2), A177682, A177684, A177685.

Programs

  • Magma
    [191, 1587, 14161] cat [2*4^(n+5)-2017*2^(n-1): n in [3..25]]; // Vincenzo Librandi, Sep 24 2013
  • Mathematica
    Join[{191,1587,14161},Transpose[NestList[{Last[#],6Last[#]-8First[#]}&,{123004,508152},20]][[1]]]  (* Harvey P. Dale, Mar 06 2011 *)
    CoefficientList[Series[(191 + 441 x + 6167 x^2 + 50734 x^3 - 116584 x^4)/((1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)
    LinearRecurrence[{6,-8},{191,1587,14161,123004,508152},20] (* Harvey P. Dale, Oct 16 2019 *)
  • PARI
    {m=19; v=concat([191, 1587, 14161, 123004, 508152], vector(m-5)); for(n=6 ,m, v[n]=6*v[n-1]-8*v[n-2]); v}
    

Formula

a(n) = 2*4^(n+5)-2017*2^(n-1) for n > 2.
G.f.: (191+441*x+6167*x^2+50734*x^3-116584*x^4) / ((1-2*x)*(1-4*x)).
G.f. for the sequence starting at a(3): 4*x^3*(30751-57468*x) / ((1-2*x)*(1-4*x)).

A177685 a(n) = 6*a(n-1)-8*a(n-2) for n > 4; a(0)=603, a(1)=4731, a(2)=58834, a(3)=254204, a(4)=1032696.

Original entry on oeis.org

603, 4731, 58834, 254204, 1032696, 4162544, 16713696, 66981824, 268181376, 1073233664, 4293950976, 17177836544, 68715411456, 274869776384, 1099495366656, 4398013988864, 17592120999936, 70368614088704
Offset: 0

Views

Author

Klaus Brockhaus, May 12 2010

Keywords

Comments

Related to Reverse and Add trajectory of 537 in base 2: a(n) = A077076(4*n+3)/6, i.e., one sixth of fourth quadrisection of A077076.

Crossrefs

Cf. A077076 (Reverse and Add trajectory of 537 in base 2), A177682, A177683, A177684.

Programs

  • Magma
    [603, 4731, 58834] cat [4^(n+6)-1985*2^(n-1): n in [3..25]]; // Vincenzo Librandi, Sep 24 2013
  • Mathematica
    CoefficientList[Series[(603 + 1113 x + 35272 x^2 - 60952 x^3 - 21856 x^4)/((1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)
    LinearRecurrence[{6,-8},{603,4731,58834,254204,1032696},20] (* Harvey P. Dale, May 26 2019 *)
  • PARI
    {m=18; v=concat([603, 4731, 58834, 254204, 1032696], vector(m-5)); for(n=6 ,m, v[n]=6*v[n-1]-8*v[n-2]); v}
    

Formula

a(n) = 4^(n+6)-1985*2^(n-1) for n > 2.
G.f.: (603+1113*x+35272*x^2-60952*x^3-21856*x^4) / ((1-2*x)*(1-4*x)).
G.f. for the sequence starting at a(3): 4*x^3*(63551-123132*x) / ((1-2*x)*(1-4*x)).
Showing 1-4 of 4 results.