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.

A155658 a(n) = 11^n + 7^n - 1.

Original entry on oeis.org

1, 17, 169, 1673, 17041, 177857, 1889209, 20310713, 220123681, 2398301297, 26219899849, 287288997353, 3152269663921, 34619601154337, 380428056656089, 4181995730925593, 45982962794141761, 505679659013280977
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

Crossrefs

Programs

Formula

G.f.: 1/(1-11*x) + 1/(1-7*x) - 1/(1-x).
E.g.f.: exp(11*x) + exp(7*x) - exp(x).
a(n) = 18*a(n-1)-77*a(n-2)-60 with a(0)=1, a(1)=17. - Vincenzo Librandi, Jul 21 2010

A155644 a(n) = 11^n-5^n+1.

Original entry on oeis.org

1, 7, 97, 1207, 14017, 157927, 1755937, 19409047, 213968257, 2355994567, 25927658977, 285262842487, 3138184236097, 34521491440807, 379743730067617, 4177217651837527, 45949577275681537, 505446265559840647
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 30 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[11^n-5^n+1,{n,0,20}] (* or *) LinearRecurrence[{17, -71, 55}, {1, 7, 97}, 20] (* Harvey P. Dale, Jul 11 2011 *)
  • PARI
    a(n)=11^n-5^n+1 \\ Charles R Greathouse IV, Jun 11 2015

Formula

G.f.: 1/(1-11*x)-1/(1-5*x)+1/(1-x).
E.g.f.: e^(11*x)-e^(5*x)+e^x.
a(n) = 16*a(n-1)-55*a(n-2)+40 with a(0)=1, a(1)=7. - Vincenzo Librandi, Jul 21 2010
a(0)=1, a(1)=7, a(2)=97, a(n) = 17*a(n-1)-71*a(n-2)+55*a(n-3). - Harvey P. Dale, Jul 11 2011

A155653 10^n-6^n+1.

Original entry on oeis.org

1, 5, 65, 785, 8705, 92225, 953345, 9720065, 98320385, 989922305, 9939533825, 99637202945, 997823217665, 9986939305985, 99921635835905, 999529815015425, 9997178890092545, 99983073340555265, 999898440043331585
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

Crossrefs

Programs

Formula

G.f.: 1/(1-10*x)-1/(1-6*x)+1/(1-x). E.g.f.: e^(10*x)-e^(6*x)+e^x.
a(n)=16*a(n-1)-60*a(n-2)+45 with a(0)=1, a(1)=5 - Vincenzo Librandi, Jul 21 2010

A155659 a(n) = 8^n - 7^n + 1.

Original entry on oeis.org

1, 2, 16, 170, 1696, 15962, 144496, 1273610, 11012416, 93864122, 791266576, 6612607850, 54878189536, 452866803482, 3719823438256, 30436810578890, 248242046141056, 2019169299698042, 16385984911571536, 132716292890482730, 1073129238309234976, 8664826172771491802
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

Crossrefs

Programs

Formula

G.f.: 1/(1-8*x)-1/(1-7*x)+1/(1-x).
E.g.f.: exp(8*x)-exp(7*x)+exp(x).
a(n) = 15*a(n-1)-56*a(n-2)+42 with a(0) = 1, a(1) = 2. - Vincenzo Librandi, Jul 21 2010

A155645 a(n) = 7^n+6^n-1.

Original entry on oeis.org

1, 12, 84, 558, 3696, 24582, 164304, 1103478, 7444416, 50431302, 342941424, 2340123798, 16018069536, 109949704422, 756587236944, 5217746494518, 36054040477056, 249557173431942, 1729973554578864, 12008254925383638
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[7^n+6^n-1,{n,0,20}] (* or *) LinearRecurrence[{14,-55,42},{1,12,84},20] (* Harvey P. Dale, May 08 2012 *)
  • PARI
    a(n)=7^n+6^n-1 \\ Charles R Greathouse IV, Jun 11 2015

Formula

G.f.: 1/(1-7*x)+1/(1-6*x)-1/(1-x).
E.g.f.: e^(7*x)+e^(6*x)-e^x.
a(n) = 13*a(n-1)-42*a(n-2)-30 with a(0)=1, a(1)=12. - Vincenzo Librandi, Jul 21 2010
a(0)=1, a(1)=12, a(2)=84, a(n) = 14*a(n-1)-55*a(n-2)+42*a(n-3). - Harvey P. Dale, May 08 2012

A155660 a(n) = 9^n - 7^n + 1.

Original entry on oeis.org

1, 3, 33, 387, 4161, 42243, 413793, 3959427, 37281921, 347066883, 3204309153, 29403732867, 268588249281, 2444976817923, 22198569382113, 201143570584707, 1819787258282241, 16444551185679363, 148466221699088673, 1339452822487618947, 12077873192759316801, 108860443267429075203
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

Crossrefs

Programs

Formula

G.f.: 1/(1-9*x)-1/(1-7*x)+1/(1-x).
E.g.f.: exp(9*x)-exp(7*x)+exp(x).
a(n) = 16*a(n-1)-63*a(n-2)+48 with a(0) = 1, a(1) = 3. - Vincenzo Librandi, Jul 21 2010

A155661 a(n) = 10^n - 7^n + 1.

Original entry on oeis.org

1, 4, 52, 658, 7600, 83194, 882352, 9176458, 94235200, 959646394, 9717524752, 98022673258, 986158712800, 9903110989594, 99321776927152, 995252438490058, 9966767069430400, 99767369486012794, 998371586402089552
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[10^n-7^n+1,{n,0,20}] (* or *) LinearRecurrence[{18,-87,70},{1,4,52}, 21] (* Harvey P. Dale, May 05 2011 *)
  • PARI
    a(n)=10^n-7^n+1 \\ Charles R Greathouse IV, Jun 11 2015

Formula

G.f.: 1/(1-10*x)-1/(1-7*x)+1/(1-x).
E.g.f.: e^(10*x)-e^(7*x)+e^x.
a(n) = 17*a(n-1)-70*a(n-2)+54 with a(0)=1, a(1)=4. - Vincenzo Librandi, Jul 21 2010
a(0)=1, a(1)=4, a(2)=52, a(n)=18*a(n-1)-87*a(n-2)+70*a(n-3). - Harvey P. Dale, May 05 2011

A155662 a(n) = 11^n - 7^n + 1.

Original entry on oeis.org

1, 5, 73, 989, 12241, 144245, 1653913, 18663629, 208594081, 2317594085, 25654949353, 283334343869, 3124587089521, 34425823133525, 379071610510393, 4172500607905709, 45916496933002561, 505214397985306565, 5558288899894321033, 61147691553229173149
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

Crossrefs

Programs

Formula

G.f.: 1/(1-11*x) - 1/(1-7*x) + 1/(1-x).
E.g.f.: e^(11*x) - e^(7*x) + e^x.
a(n) = 18*a(n-1) - 77*a(n-2) + 60; a(0)=1, a(1)=5. - Vincenzo Librandi, Jul 21 2010

A217696 Let p = A002145(n) be the n-th prime of the form 4k+3, then a(n) is the smallest number such that p is the smallest prime of the form 4k+3 for which 4*a(n)+2-p is prime.

Original entry on oeis.org

1, 4, 10, 24, 76, 102, 196, 74, 104, 348, 314, 345, 86, 660, 443, 1494, 914, 1329, 2613, 1635, 1316, 1856, 1688, 2589, 2628, 6423, 3116, 2165, 6320, 4445, 7278, 4743, 16539, 17783, 6084, 3806, 6281, 8946, 15129, 6266, 10976, 19538, 16794, 31160, 32916, 57041
Offset: 1

Views

Author

Lei Zhou, Mar 19 2013

Keywords

Comments

It is conjectured that a(n) is defined for all positive integers.
This is also the index of first occurrence of the n-th prime in the form of 4k+3 in A214834.

Examples

			n=1: the first prime in the form of 4k+3 is 3, 3+3=6=4*1+2, so a(1)=1;
n=2: the second prime in the form of 4k+3 is 7, 7+7=14=3+11=4*3+2, and 11 is also a prime in the form of 4k+3, so a(2)!=3. 7+11=18=4*4+2=3+15, and 15 is not a prime number. So a(2)=4.
		

Crossrefs

Programs

  • Mathematica
    goal = 46; plst = {}; pct = 0; clst = {}; n = -1; While[pct < goal,
    n = n + 4; If[PrimeQ[n], AppendTo[plst, n]; AppendTo[clst, 0];
      pct++]]; n = 2; cct = 0; While[cct < goal, n = n + 4; p1 = n + 1;
    While[p1 = p1 - 4; p2 = n - p1; ! ((PrimeQ[p1]) && (PrimeQ[p2]) && (Mod[p2, 4] == 3))]; If[MemberQ[plst, p2], If[id = Position[plst, p2][[1, 1]]; clst[[id]] == 0, clst[[id]] = (n - 2)/4; cct++]]]; clst
  • PARI
    ok(n,p)=if(!isprime(n-p),return(0));forprime(q=2,p-1,if(q%4==3 && isprime(n-q),return(0)));1
    a(n)=my(p,k); forprime(q=2,,if(q%4==3&&n--==0,p=q;break)); k=(p+1)/4; while(!ok(4*k+2,p),k++); k \\ Charles R Greathouse IV, Mar 19 2013
Previous Showing 11-19 of 19 results.