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 11-16 of 16 results.

A017459 a(n) = (11*n + 5)^11.

Original entry on oeis.org

48828125, 17592186044416, 5559060566555523, 238572050223552512, 3909821048582988049, 36279705600000000000, 231122292121701565271, 1127073856954876807168, 4501035456767426597157, 15394540563150776827904
Offset: 0

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Author

Keywords

Crossrefs

Powers of the form (11*n+5)^m: A017449 (m=1), A017450 (m=2), A017451 (m=3), A017452 (m=4), A017453 (m=5), A017454 (m=6), A017455 (m=7), A017456 (m=8), A017457 (m=9), A017458 (m=10), this sequence (m=11), A017460 (m=12).

Programs

Formula

From G. C. Greubel, Sep 19 2019: (Start)
G.f.: (48828125 +17591600106916*x +5347957556678781*x^2 + 173024396961630192*x^3 +1409984186533172778*x^4 +3893323100536505064*x^5 +4065965093212217778*x^6 +1612934439380337744*x^7 +220215589053761433* x^8 +7882270656385972*x^9 +34267542742961*x^10 +362797056*x^11)/(1-x)^12.
E.g.f.: (48828125 +17592137216291*x +2761938121647408*x^2 + 36991274172198511*x^3 +124534035099698400*x^4 +158840151787803530*x^5 + 93615574446397542*x^6 +28270098736853457*x^7 +4580560974275055*x^8 + 396972283518305*x^9 +17118700236660*x^10 +285311670611*x^11)*exp(x). (End)

A017460 a(n) = (11*n + 5)^12.

Original entry on oeis.org

244140625, 281474976710656, 150094635296999121, 9065737908494995456, 191581231380566414401, 2176782336000000000000, 16409682740640811134241, 92420056270299898187776, 418596297479370673535601, 1601032218567680790102016
Offset: 0

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Author

Keywords

Crossrefs

Powers of the form (11*n+5)^m: A017449 (m=1), A017450 (m=2), A017451 (m=3), A017452 (m=4), A017453 (m=5), A017454 (m=6), A017455 (m=7), A017456 (m=8), A017457 (m=9), A017458 (m=10), A017459 (m=11), this sequence (m=12).

Programs

Formula

From G. C. Greubel, Sep 19 2019: (Start)
G.f.: (244140625 +281471802882531*x +146435479642729343*x^2 + 7136462627993219301*x^3 +85353518454518704170*x^4 +350628073514443644414 *x^5 +569002784856695826846*x^6 +380284494715132979466*x^7 + 101126771751016700469*x^8 +9408164121360836975*x^9 +224644345794247731* x^10 +582593939059393*x^11 +2176782336*x^12)/(1-x)^13.
E.g.f.: (244140625 +281474732570031*x +74765842793859217*x^2 + 1436049737881664906*x^3 +6509071735779405221*x^4 +10900283493364894200* x^5 +8393947455360064312*x^6 +3347919415332356436*x^7 + 736963256712968142*x^8 +91671288202929325*x^9 +6335345645917255*x^10 + 224254973100246*x^11 +3138428376721*x^12)*exp(x). (End)

A083487 Triangle read by rows: T(n,k) = 2*n*k + n + k (1 <= k <= n).

Original entry on oeis.org

4, 7, 12, 10, 17, 24, 13, 22, 31, 40, 16, 27, 38, 49, 60, 19, 32, 45, 58, 71, 84, 22, 37, 52, 67, 82, 97, 112, 25, 42, 59, 76, 93, 110, 127, 144, 28, 47, 66, 85, 104, 123, 142, 161, 180, 31, 52, 73, 94, 115, 136, 157, 178, 199, 220, 34, 57, 80, 103, 126, 149, 172, 195, 218, 241, 264
Offset: 1

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Author

Artemario Tadeu Medeiros da Silva (artemario(AT)uol.com.br), Jun 09 2003

Keywords

Comments

T(n,k) gives number of edges (of unit length) in a k X n grid.
The values 2*T(n,k)+1 = (2*n+1)*(2*k+1) are nonprime and therefore in A047845.

Examples

			Triangle begins:
   4;
   7, 12;
  10, 17, 24;
  13, 22, 31, 40;
  16, 27, 38, 49,  60;
  19, 32, 45, 58,  71,  84;
  22, 37, 52, 67,  82,  97, 112;
  25, 42, 59, 76,  93, 110, 127, 144;
  28, 47, 66, 85, 104, 123, 142, 161, 180;
		

Crossrefs

Programs

  • Magma
    [(2*n*k + n + k): k in [1..n], n in [1..11]]; // Vincenzo Librandi, Jun 01 2014
    
  • Mathematica
    T[n_,k_]:= 2 n k + n + k; Table[T[n, k], {n, 10}, {k, n}]//Flatten (* Vincenzo Librandi, Jun 01 2014 *)
  • Python
    def T(r, c): return 2*r*c + r + c
    a = [T(r, c) for r in range(12) for c in range(1, r+1)]
    print(a) # Michael S. Branicky, Sep 07 2022
    
  • SageMath
    flatten([[2*n*k +n +k for k in range(1,n+1)] for n in range(1,14)]) # G. C. Greubel, Oct 17 2023

Formula

From G. C. Greubel, Oct 17 2023: (Start)
T(n, 1) = A016777(n).
T(n, 2) = A016873(n).
T(n, 3) = A017017(n).
T(n, 4) = A017209(n).
T(n, 5) = A017449(n).
T(n, 6) = A186113(n).
T(n, n-1) = A056220(n).
T(n, n-2) = A090288(n-2).
T(n, n-3) = A271625(n-2).
T(n, n) = 4*A000217(n).
T(2*n, n) = A033954(n).
Sum_{k=1..n} T(n, k) = A162254(n).
Sum_{k=1..n} (-1)^(k-1)*T(n, k) = A182868((n+1)/2) if n is odd otherwise A182868(n/2) + 1. (End)

Extensions

Edited by N. J. A. Sloane, Jul 23 2009
Name edited by Michael S. Branicky, Sep 07 2022

A153384 Numbers n such that 24*n+1 is not prime.

Original entry on oeis.org

0, 1, 2, 5, 6, 7, 9, 11, 12, 15, 16, 20, 21, 22, 23, 26, 27, 29, 30, 31, 33, 34, 35, 36, 37, 38, 40, 41, 44, 45, 46, 49, 51, 53, 56, 57, 58, 59, 60, 61, 63, 64, 65, 66, 68, 70, 71, 72, 76, 77, 79, 80, 81, 82, 85, 86, 91, 92, 93, 94, 96, 97, 98, 100, 101, 102
Offset: 1

Views

Author

Vincenzo Librandi, Dec 25 2008

Keywords

Comments

Contains all numbers == 1 (mod 5), ==2 (mod 7), ==5 (mod 11), == 7 (mod 13), == 12 (mod 17), == 15 (mod 19), == 22 (mod 23), == 6 (mod 29) etc, so it is the union of A016861, A017005, A017449, A269044, etc. - R. J. Mathar, Jun 10 2020
Even terms of A153383, halved. - R. J. Mathar, Jun 10 2020

Examples

			Triangle begins:
*;
*,1;
*,*,2;
*,*,*,*;
*,*,*,*,5;
*,*,*,*,*,7;
*,*,*,*,*,*,*;
*,*,*,*,*,*,*,12;
*,*,*,*,*,*,*,*,15;
*,*,*,*,*,*,*,*,*,*;
*,*,*,*,*,*,*,*,*,*,22; etc.
where * marks the non-integer values of (2*h*k + k + h)/12 with h >= k >= 1. - _Vincenzo Librandi_, Jan 14 2013
		

Crossrefs

Cf. A001318, A111174 (complement).

Programs

  • Magma
    [n: n in [0..150] | not IsPrime(24*n + 1)]; // Vincenzo Librandi, Jan 14 2013
  • Mathematica
    Select[Range[0, 200], !PrimeQ[24 # + 1] &] (* Vincenzo Librandi, Jan 14 2013 *)

Extensions

0 added by Arkadiusz Wesolowski, Aug 03 2011

A168463 a(n) = 5 + 11*floor(n/2).

Original entry on oeis.org

5, 16, 16, 27, 27, 38, 38, 49, 49, 60, 60, 71, 71, 82, 82, 93, 93, 104, 104, 115, 115, 126, 126, 137, 137, 148, 148, 159, 159, 170, 170, 181, 181, 192, 192, 203, 203, 214, 214, 225, 225, 236, 236, 247, 247, 258, 258, 269, 269, 280, 280, 291, 291, 302, 302, 313
Offset: 1

Views

Author

Vincenzo Librandi, Nov 26 2009

Keywords

Crossrefs

Cf. A017449.

Programs

  • Magma
    [5+11*Floor(n/2): n in [1..70]]; // Vincenzo Librandi, Sep 19 2013
  • Mathematica
    Table[5 + 11 Floor[n/2], {n, 70}] (* or *) CoefficientList[Series[(5 + 11 x - 5 x^2)/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 19 2013 *)
    LinearRecurrence[{1,1,-1},{5,16,16},80] (* Harvey P. Dale, Aug 28 2019 *)

Formula

a(n) = 11*n - a(n-1) - 1, with n>1, a(1)=5.
G.f.: x*(5 + 11*x - 5*x^2)/((1+x)*(x-1)^2). - Vincenzo Librandi, Sep 19 2013
a(n) = a(n-1) +a(n-2) -a(n-3). - Vincenzo Librandi, Sep 19 2013
From G. C. Greubel, Jul 23 2016: (Start)
a(n) = (22*n + 11*(-1)^n + 9)/4.
E.g.f.: (1/4)*(11 - 20*exp(x) + (22*x + 9)*exp(2*x))*exp(-x). (End)

Extensions

New definition by Vincenzo Librandi, Sep 19 2013

A355668 Array read by upwards antidiagonals T(n,k) = J(k) + n*J(k+1) where J(n) = A001045(n) is the Jacobsthal numbers.

Original entry on oeis.org

0, 1, 1, 2, 2, 1, 3, 3, 4, 3, 4, 4, 7, 8, 5, 5, 5, 10, 13, 16, 11, 6, 6, 13, 18, 27, 32, 21, 7, 7, 16, 23, 38, 53, 64, 43, 8, 8, 19, 28, 49, 74, 107, 128, 85, 9, 9, 22, 33, 60, 95, 150, 213, 256, 171, 10, 10, 25, 38, 71, 116, 193, 298, 427, 512, 341
Offset: 0

Views

Author

Paul Curtz, Jul 13 2022

Keywords

Examples

			Row n=0 is A001045(k), then for further rows we successively add A001045(k+1).
       k=0  k=2  k=3  k=4  k=5  k=6  k=7  k=8  k=9 k=10
  n=0:  0    1    1    3    5   11   21   43   85  171 ... = A001045
  n=1:  1    2    4    8   16   32   64  128  256  512 ... = A000079
  n=2:  2    3    7   13   27   53  107  213  427  853 ... = A048573
  n=3:  3    4   10   18   38   74  150  298  598 1194 ... = A171160
  n=4:  4    5   13   23   49   95  193  383  769 1535 ... = abs(A140683)
  ...
		

Crossrefs

Antidiagonal sums give A320933(n+1).

Programs

  • Mathematica
    T[n_, k_] := (2^k - (-1)^k + n*(2^(k + 1) + (-1)^k))/3; Table[T[n - k, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Amiram Eldar, Jul 13 2022 *)

Formula

T(n, k) = (2^k - (-1)^k + n*(2^(k + 1) + (-1)^k))/3.
G.f.: (x*(y-1) - y)/((x - 1)^2*(y + 1)*(2*y - 1)). - Stefano Spezia, Jul 13 2022
Previous Showing 11-16 of 16 results.