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 1-7 of 7 results.

A082977 Numbers that are congruent to {0, 1, 3, 5, 6, 8, 10} mod 12.

Original entry on oeis.org

0, 1, 3, 5, 6, 8, 10, 12, 13, 15, 17, 18, 20, 22, 24, 25, 27, 29, 30, 32, 34, 36, 37, 39, 41, 42, 44, 46, 48, 49, 51, 53, 54, 56, 58, 60, 61, 63, 65, 66, 68, 70, 72, 73, 75, 77, 78, 80, 82, 84, 85, 87, 89, 90, 92, 94, 96, 97, 99, 101, 102, 104, 106, 108, 109, 111
Offset: 1

Views

Author

N. J. A. Sloane, May 31 2003

Keywords

Comments

James Ingram suggests that this (with the initial 0 omitted) is the correct version of Fludd's sequence, rather than A047329. See also A083026.
Key-numbers of the pitches of a Hypophrygian mode scale on a standard chromatic keyboard, with root = 0. A Hypophrygian mode scale can, for example, be played on consecutive white keys of a standard keyboard, starting on the root tone B. - James Ingram (j.ingram(AT)t-online.de), Jun 01 2003

References

  • Robert Fludd, Utriusque Cosmi ... Historia, Oppenheim, 1617-1619.

Crossrefs

Cf. A047329. Different from A000210.
A guide for some sequences related to modes and chords:
Modes:
Lydian mode (F): A083089
Ionian mode (C): A083026
Mixolydian mode (G): A083120
Dorian mode (D): A083033
Aeolian mode (A): A060107 (raised seventh: A083028)
Phrygian mode (E): A083034
Locrian mode (B): this sequence
Chords:
Major chord: A083030
Minor chord: A083031
Dominant seventh chord: A083032

Programs

  • Haskell
    a082977 n = a082977_list !! (n-1)
    a082977_list = [0, 1, 3, 5, 6, 8, 10] ++ map (+ 12) a082977_list
    -- Reinhard Zumkeller, Jan 07 2014
    
  • Magma
    [n : n in [0..150] | n mod 12 in [0, 1, 3, 5, 6, 8, 10]]; // Wesley Ivan Hurt, Jul 19 2016
    
  • Maple
    A082977:=n->12*floor(n/7)+[0, 1, 3, 5, 6, 8, 10][(n mod 7)+1]: seq(A082977(n), n=0..100); # Wesley Ivan Hurt, Jul 19 2016
  • Mathematica
    CoefficientList[Series[x(1 + x + 2*x^4)(1 + x + x^2)/((1 - x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)), {x, 0, 100}], x] (* Vincenzo Librandi, Jan 06 2013 *)
    fQ[n_] := MemberQ[{0, 1, 3, 5, 6, 8, 10}, Mod[n, 12]]; Select[ Range[0, 111], fQ] (* Robert G. Wilson v, Jan 07 2014 *)
    LinearRecurrence[{1, 0, 0, 0, 0, 0, 1, -1}, {0, 1, 3, 5, 6, 8, 10, 12}, 70] (* Jianing Song, Sep 22 2018 *)
    Floor@Range[0,2^8,12/7] (* Federico Provvedi, Oct 18 2018 *)
  • PARI
    x='x+O('x^99); concat(0, Vec(x*(1+x+2*x^4)*(1+x+x^2)/((1-x)^2*(1+x+x^2+x^3+x^4+x^5+x^6)))) \\ Jianing Song, Sep 22 2018

Formula

G.f.: x*(1 + x + 2*x^4)*(1 + x + x^2)/((1 - x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)). - R. J. Mathar, Sep 17 2008
From Wesley Ivan Hurt, Jul 19 2016: (Start)
a(n) = a(n-1) + a(n-7) - a(n-8) for n > 8.
a(n) = (84*n - 105 - 2*(n mod 7) - 2*((n + 1) mod 7) + 5*((n + 2) mod 7) - 2*((n + 3) mod 7) - 2*((n + 4) mod 7) + 5*((n + 5) mod 7) - 2*((n + 6) mod 7))/49.
a(7k) = 12k - 2, a(7k-1) = 12k - 4, a(7k-2) = 12k - 6, a(7k-3) = 12k - 7, a(7k-4) = 12k - 9, a(7k-5) = 12k - 11, a(7k-6) = 12k - 12. (End)
a(n) = a(n-7) + 12 for n > 7. - Jianing Song, Sep 22 2018
a(n) = floor(12*(n-1)/7). - Federico Provvedi, Oct 18 2018

A185616 Lower Wythoff values for sequence A185615(n).

Original entry on oeis.org

1, 6, 12, 40, 80, 174, 273, 393, 414, 546, 786, 828, 1179, 1242, 1572, 1656, 1870, 1965, 3740, 5460, 8090, 12816, 13254, 14154, 16180, 20710, 24270, 25632, 32360, 40450, 81186, 87841, 137830, 142725, 162372, 169854, 175682, 212078, 285450
Offset: 1

Views

Author

Paul D. Hanna and Sean A. Irvine, Jan 31 2011

Keywords

Comments

Lower Wythoff values for sequence A185615(n)

Crossrefs

Formula

A187472 Rank transform of the sequence floor((e-1)n); complement of A187473.

Original entry on oeis.org

1, 3, 5, 7, 9, 11, 13, 14, 17, 18, 20, 22, 24, 26, 28, 30, 32, 33, 35, 38, 40, 41, 43, 45, 47, 49, 51, 53, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 115, 117, 119, 121, 123, 125
Offset: 1

Views

Author

Clark Kimberling, Mar 10 2011

Keywords

Comments

See A187224.

Crossrefs

Programs

  • Mathematica
    m = E-1;
    seqA = Table[Floor[m*n], {n, 1, 180}]  (* A000210 *)
    seqB = Table[n, {n, 1, 80}];           (* A000027 *)
    jointRank[{seqA_, seqB_}] := {Flatten@Position[#1, {_, 1}],
    Flatten@Position[#1, {_, 2}]} &[Sort@Flatten[{{#1, 1} & /@ seqA,
    {#1, 2} & /@ seqB}, 1]];
    limseqU = FixedPoint[jointRank[{seqA, #1[[1]]}] &, jointRank[{seqA, seqB}]][[1]]                                     (* A187472 *)
    Complement[Range[Length[seqA]], limseqU]  (* A187473 *)
    (* by Peter J. C. Moses, Mar 10 2011 *)

A279590 Coefficients in the expansion of 1/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = e - 1.

Original entry on oeis.org

1, -3, 4, -3, -1, 8, -15, 18, -13, -3, 30, -63, 89, -86, 29, 97, -278, 453, -511, 314, 245, -1151, 2170, -2795, 2305, -6, -4331, 9921, -14534, 14549, -5887, -13958, 43029, -72127, 83898, -55979, -30079, 174330, -342124, 454087, -393943, 45299, 638945
Offset: 0

Views

Author

Clark Kimberling, Dec 16 2016

Keywords

Crossrefs

Cf. A000210.

Programs

  • Mathematica
    z = 30; r = E - 1;
    f[x_] := f[x] = Sum[Floor[r*(k + 1)] x^k, {k, 0, z}]; f[x]
    CoefficientList[Series[1/f[x], {x, 0, 2*z}], x]

Formula

G.f.: 1/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = e - 1.

A279632 Coefficients in the expansion of ([s] + [2s]x + [3s]x^2 + ...)/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = e - 1, s = r/(1-r).

Original entry on oeis.org

2, -2, 3, -2, -2, 8, -14, 17, -12, -5, 34, -68, 91, -80, 11, 126, -308, 467, -488, 235, 382, -1316, 2291, -2760, 1995, 638, -5220, 10738, -14725, 13447, -3007, -18467, 47914, -74806, 80821, -43890, -51936, 201548, -363193, 450980, -347117, -55972, 782359
Offset: 0

Views

Author

Clark Kimberling, Dec 18 2016

Keywords

Crossrefs

Programs

  • Mathematica
    z = 100;
    r = E - 1; f[x_] := f[x] = Sum[Floor[r*(k + 1)] x^k, {k, 0, z}];
    s = r/(r - 1); g[x_] := g[x] = Sum[Floor[s*(k + 1)] x^k, {k, 0, z}]
    CoefficientList[Series[g[x]/f[x], {x, 0, z}], x]

Formula

G.f.: ([s] + [2s]x + [3s]x^2 + ...)/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = sqrt(2), s = r/(1-r).

A332502 Rectangular array read by antidiagonals: T(n,k) = floor(n + k*r), where r = golden ratio = (1+sqrt(5))/2.

Original entry on oeis.org

0, 1, 1, 3, 2, 2, 4, 4, 3, 3, 6, 5, 5, 4, 4, 8, 7, 6, 6, 5, 5, 9, 9, 8, 7, 7, 6, 6, 11, 10, 10, 9, 8, 8, 7, 7, 12, 12, 11, 11, 10, 9, 9, 8, 8, 14, 13, 13, 12, 12, 11, 10, 10, 9, 9, 16, 15, 14, 14, 13, 13, 12, 11, 11, 10, 10, 17, 17, 16, 15, 15, 14, 14, 13
Offset: 0

Views

Author

Clark Kimberling, May 08 2020

Keywords

Comments

Every nonnegative integer occurs exactly once in the union of row 0 and the main diagonal.
Column 0: Nonnegative integers, A001477.
Row 0: Lower Wythoff sequence, A000201.
Row 1: A026351.
Row 2: A026355 (and essentially A099267).
Main Diagonal: Upper Wythoff sequence, A001950.
Diagonal (1,4,6,9,...) = A003622;
Diagonal (3,5,8,11,...) = A026274;
Diagonal (1,3,6,8,...) = A026352;
Diagonal (2,4,7,9,...) = A026356.

Examples

			Northwest corner:
  0   1   3   4   6   8    9    11   12   14   16
  1   2   4   5   7   9    10   12   13   15   17
  2   3   5   6   8   10   11   13   14   16   18
  3   4   6   7   9   11   12   14   15   17   19
  4   5   7   8   10  12   13   15   16   18   20
  5   6   8   9   11  13   14   16   17   19   21
As a triangle (antidiagonals):
  0
  1   1
  2   2   3
  3   3   4   4
  4   4   5   5   6
  5   5   6   6   7   8
  6   6   7   7   8   9   9
		

Crossrefs

Programs

  • Mathematica
    t[n_, k_] := Floor[n + k*GoldenRatio];
    Grid[Table[t[n, k], {n, 0, 10}, {k, 0, 10}]] (* array *)
    u = Table[t[n - k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten  (* sequence *)

Formula

T(n,k) = floor(n + k*r), where r = golden ratio = (1+sqrt(5))/2.

A340534 a(n) is the least product of n consecutive primes that is divisible by the sum of those primes, or 0 if there is no such product.

Original entry on oeis.org

2, 0, 30, 0, 15015, 0, 37182145, 9699690, 33426748355, 0, 3710369067405, 0, 304250263527210, 0, 37420578814667938361329, 0, 18598027670889965365580513, 0, 107254825578022430263302818471, 0, 44510752614879308559270669665465, 0, 267064515689275851355624017992790, 0, 116431182179248680450031658440253681535, 0
Offset: 1

Views

Author

J. M. Bergot and Robert Israel, Jan 10 2021

Keywords

Comments

a(27) > 10^225 if it is not 0.
If n is even, a(n) is either A002110(n) or 0.
a(n) = A002110(n) for n in A051838.

Examples

			a(5) = 15015 = 3*5*7*11*13 is the product of 5 consecutive primes and is divisible by 3+5+7+11+13 = 39.
		

Crossrefs

Programs

  • Maple
    f:= proc(n) local L,i,p;
       L:= [seq(ithprime(i),i=1..n)]:
       p:= convert(L,`*`);
       if n::even then
         if p mod convert(L,`+`) = 0 then return p else return 0 fi
       else
         do
           p:= convert(L,`*`);
           if p mod convert(L,`+`) = 0 then return p fi;
           if p > 10^225 then return FAIL fi;
           L:= [op(L[2..-1]),nextprime(L[-1])];
         od
       fi;
    end proc:
    map(f, [$1..26]);
Showing 1-7 of 7 results.