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 1-8 of 8 results.

A050926 Binary representation of A007908(n).

Original entry on oeis.org

1, 1100, 1111011, 10011010010, 11000000111001, 11110001001000000, 100101101011010000111, 101111000110000101001110, 111010110111100110100010101, 1011011111110111000001110000111110
Offset: 1

Views

Author

Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 30 1999

Keywords

Links

Crossrefs

Cf. A007908, A097580, A097582, A097583.
Cf. A007088.

Formula

a(n) = A007088(A007908(n)). - Seiichi Manyama, Apr 23 2022

A097580 Base 3 representation of the concatenation of the first n numbers with the most significant digits first.

Original entry on oeis.org

1, 110, 11120, 1200201, 121221020, 20021100110, 2022201111201, 212020020002100, 22121022020212200, 1011212101120110200001, 11101000122011021220211010, 121012010100112220022220220120
Offset: 1

Views

Author

Cino Hilliard, Aug 29 2004

Keywords

Comments

Consider numbers of the form 1, 12, 123, 1234, ..., N. Find the highest power of 3^p such that 3^p <= N. Then p = [log(N)/log(3)] and for 0 <= qi <= 2 [N/3^p] = q1 + r1 [r1/3^(p-1)] = q2 + r2 ........................ rp/3^1 = qp + rp+1 rp+1/3^0 = qp+1 0 For N = 1234, p = [log(1234)/log(3)] = 6 division quot rem 1234/3^6 = 1 505 505/3^5 = 2 19 19/3^4 = 0 19 19/3^3 = 0 19 19/3^2 = 2 1 1/3^1 = 0 1 1/3^0 = 1 0 The sequence of quotients, top down, form the entry in the table for 1234. Obviously this algorithm works for any N.

Examples

			The 4th concatenation of the integers > 0 is 1234. base(10,3,1234) = 1200201 the 4th entry in the table.

Links

Crossrefs

Cf. A007908, A050926, A097582, A097583.
Cf. A007089.

Programs

  • Mathematica
    Table[FromDigits[IntegerDigits[FromDigits[Flatten[Table[ IntegerDigits[n],{n,i}]]],3]],{i,12}] (* Harvey P. Dale, May 23 2011 *)

Formula

a(n) = A007089(A007908(n)). - Seiichi Manyama, Apr 23 2022

A097582 Base 7 representation of the concatenation of the first n numbers with the most significant digits first.

Original entry on oeis.org

1, 15, 234, 3412, 50664, 1022634, 13331215, 206636142, 3026236221, 614636352655, 155123512633260, 35001313215554565, 10403265603212022112, 2132066345452131466644, 434014101450663623262042
Offset: 1

Views

Author

Cino Hilliard, Aug 29 2004

Keywords

Comments

Consider numbers of the form 1, 12, 123, 1234, ..., N. Find the highest power of 7^p such that 7^p < N. Then p = [log(N)/log(7)] and for 0 <= qi <= 6 [N/7^p] = q1 + r1 [r1/7^(p-1)] = q2 + r2 ........................ rp/7^1 = qp + rp+1 rp+1/7^0 = qp+1 0 For N = 1234, p = [log(1234)/log(7)] = 3 division quot rem 1234/7^3 = 3 205 205/7^2 = 4 9 9/7^1 = 1 2 2/7^0 = 2 0 The sequence of quotients, top down, forms the entry in the table for 1234. Obviously this algorithm works for any N.

Links

Crossrefs

Cf. A007908, A050926, A097580, A097583.
Cf. A007093.

Formula

a(n) = A007093(A007908(n)). - Seiichi Manyama, Apr 23 2022

A353116 Base-8 representation of A000422(n).

Original entry on oeis.org

1, 25, 501, 10341, 152061, 2375761, 35145661, 516277661, 7267464261, 121672446261, 20125401442261, 3342313131342261, 564731226736442261, 116343242472501442261, 20325073566675147442261, 3327107422474572347442261
Offset: 1

Views

Author

Seiichi Manyama, Apr 24 2022

Keywords

Crossrefs

Cf. A000422, A353110, A353111, A353112, A353113, A353114, A353115, A353117.
Cf. A007094, A097583.

Programs

  • Ruby
    def A(k, n)
  (1..n).map{|i| (1..i).to_a.reverse.join.to_i.to_s(k).to_i}
end
p A(8, 20)

Formula

a(n) = A007094(A000422(n)).

A353104 Base-4 representation of A007908(n).

Original entry on oeis.org

1, 30, 1323, 103102, 3000321, 132021000, 10231122013, 233012011032, 13112330310111, 23133313001300332, 101331301332300201003, 130010202012003303220320, 223313011101131330223313231, 1010202010033102302310203002202
Offset: 1

Views

Author

Seiichi Manyama, Apr 23 2022

Keywords

Links

Crossrefs

Cf. A007908, A050926, A097580, A097582, A097583, A353105, A353106, A353107.
Cf. A007090.

Programs

  • Ruby
    def A(k, n)
  (1..n).map{|i| (1..i).to_a.join.to_i.to_s(k).to_i}
end
p A(4, 20)

Formula

a(n) = A007090(A007908(n)).

A353105 Base-5 representation of A007908(n).

Original entry on oeis.org

1, 22, 443, 14414, 343340, 12422311, 304001232, 11130030203, 223101104124, 200240443211120, 130211343340003021, 112140204001002213422, 100421133100401442024323, 40324014240311242321340224, 31241112311230113034201201130
Offset: 1

Views

Author

Seiichi Manyama, Apr 23 2022

Keywords

Links

Crossrefs

Cf. A007908, A050926, A097580, A097582, A097583, A353104, A353106, A353107.
Cf. A007091.

Programs

  • Ruby
    def A(k, n)
  (1..n).map{|i| (1..i).to_a.join.to_i.to_s(k).to_i}
end
p A(5, 20)

Formula

a(n) = A007091(A007908(n)).

A353106 Base-6 representation of A007908(n).

Original entry on oeis.org

1, 20, 323, 5414, 133053, 2351320, 42243331, 1120335530, 20130035113, 5401014424514, 2343052550252003, 1114323133240053240, 321321022332303252301, 132140014431255340214310, 42015444551405453142112503
Offset: 1

Views

Author

Seiichi Manyama, Apr 23 2022

Keywords

Links

Crossrefs

Cf. A007908, A050926, A097580, A097582, A097583, A353104, A353105, A353107.
Cf. A007092.

Programs

  • Ruby
    def A(k, n)
  (1..n).map{|i| (1..i).to_a.join.to_i.to_s(k).to_i}
end
p A(6, 20)

Formula

a(n) = A007092(A007908(n)).

A353107 Base-9 representation of A007908(n).

Original entry on oeis.org

1, 13, 146, 1621, 17836, 207313, 2281451, 25206070, 277266780, 34771513601, 4330564256733, 535110486286816, 65858371163036861, 8202185121837583406, 1113465620754570813253, 134741562223525280514741, 16425841240157671153405780
Offset: 1

Views

Author

Seiichi Manyama, Apr 23 2022

Keywords

Links

Crossrefs

Cf. A007908, A050926, A097580, A097582, A097583, A353104, A353105, A353106.
Cf. A007095.

Programs

  • Ruby
    def A(k, n)
  (1..n).map{|i| (1..i).to_a.join.to_i.to_s(k).to_i}
end
p A(9, 20)

Formula

a(n) = A007095(A007908(n)).
Showing 1-8 of 8 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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