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 11-14 of 14 results.

A174371 a(n) = (6*n-1)^2.

Original entry on oeis.org

1, 25, 121, 289, 529, 841, 1225, 1681, 2209, 2809, 3481, 4225, 5041, 5929, 6889, 7921, 9025, 10201, 11449, 12769, 14161, 15625, 17161, 18769, 20449, 22201, 24025, 25921, 27889, 29929, 32041, 34225, 36481, 38809, 41209, 43681, 46225, 48841, 51529
Offset: 0

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Author

Juri-Stepan Gerasimov, Mar 17 2010

Keywords

Comments

Unit together with numbers of form (6*n+5)^2.
Sequence may be obtained by starting with the segment (1, 25) followed by the line from 25 in the direction 25, 121,... in the square spiral whose vertices are the generalized 20-gonal numbers. - Omar E. Pol, Jul 29 2016

Examples

			a(0)=1 because (6*0-1)^2=1, a(1)=25 because (6*1-1)^2=25.
		

Crossrefs

Programs

Formula

a(n) = A016970(n-1), n >= 1.
G.f.: (49*x^2 + 22*x + 1)/(1 - x)^3. - Vincenzo Librandi, Jan 27 2013
a(n) = 6*A033579(n) + 1. - Miquel Cerda, Jul 28 2016
a(n) = 36n^2 - 12n + 1. - Omar E. Pol, Jul 28 2016
E.g.f.: exp(x)*(1 + 24*x + 36*x^2). - Stefano Spezia, Aug 19 2023

Extensions

Offset and formula corrected by R. J. Mathar, Apr 16 2010

A016979 a(n) = (6*n + 5)^11.

Original entry on oeis.org

48828125, 285311670611, 34271896307633, 952809757913927, 12200509765705829, 96549157373046875, 550329031716248441, 2472159215084012303, 9269035929372191597, 30155888444737842659, 87507831740087890625, 231122292121701565271, 564154396389137449973
Offset: 0

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Author

Keywords

Crossrefs

Subsequence of A008455 (n^11).

Programs

  • Magma
    [(6*n+5)^11 : n in [0..20]]; // Vincenzo Librandi, May 17 2011
  • Mathematica
    (6Range[0,20]+5)^11 (* or *) LinearRecurrence[{12,-66,220,-495,792,-924,792,-495,220,-66,12,-1},{48828125,285311670611,34271896307633,952809757913927,12200509765705829,96549157373046875,550329031716248441,2472159215084012303,9269035929372191597,30155888444737842659,87507831740087890625,231122292121701565271},20] (* Harvey P. Dale, Dec 17 2024 *)

Formula

a(n) = (6*n + 5)^11.
From Amiram Eldar, Apr 01 2022: (Start)
a(n) = A016969(n)^11.
Sum_{n>=0} 1/a(n) = 181308931*zeta(11)/362797056 - 1261501*Pi^11/(428554022400*sqrt(3)). (End)

A017642 a(n) = (12*n+10)^2.

Original entry on oeis.org

100, 484, 1156, 2116, 3364, 4900, 6724, 8836, 11236, 13924, 16900, 20164, 23716, 27556, 31684, 36100, 40804, 45796, 51076, 56644, 62500, 68644, 75076, 81796, 88804, 96100, 103684, 111556, 119716
Offset: 0

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Author

Keywords

Examples

			a(5) = (12*5+10)^2 = 70^2 = 4900.
		

Crossrefs

Programs

  • Magma
    [(12*n+10)^2 : n in [0..40]]; // Wesley Ivan Hurt, Dec 22 2020
  • Mathematica
    (12*Range[0,30]+10)^2 (* or *) LinearRecurrence[{3,-3,1},{100,484,1156},30] (* Harvey P. Dale, May 08 2017 *)
    CoefficientList[Series[4*(25 + 46 x + x^2)/(1 - x)^3, {x, 0, 40}], x] (* Wesley Ivan Hurt, Dec 22 2020 *)
  • PARI
    a(n)=(12*n+10)^2 \\ Charles R Greathouse IV, Jun 17 2017
    

Formula

From Wesley Ivan Hurt, Dec 22 2020: (Start)
G.f.: 4*(25 + 46*x + x^2)/(1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n >= 3.
a(n) = 144*n^2 + 240*n + 100.
a(n) = A017641(n)^2. (End)

A016980 a(n) = (6*n + 5)^12.

Original entry on oeis.org

244140625, 3138428376721, 582622237229761, 21914624432020321, 353814783205469041, 3379220508056640625, 22563490300366186081, 116191483108948578241, 491258904256726154641, 1779197418239532716881, 5688009063105712890625, 16409682740640811134241, 43439888521963583647921
Offset: 0

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Author

Keywords

Crossrefs

Subsequence of A008456 (n^12).

Programs

Formula

From Amiram Eldar, Apr 01 2022: (Start)
a(n) = A016969(n)^12 = A016970(n)^6 = A016971(n)^4 = A016972(n)^3 = A016974(n)^2.
Sum_{n>=0} 1/a(n) = PolyGamma(11, 5/6)/86890185149644800. (End)
Previous Showing 11-14 of 14 results.