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 1-3 of 3 results.

A059805 Natural numbers written with digits grouped in pairs and leading zeros omitted.

Original entry on oeis.org

12, 34, 56, 78, 91, 1, 11, 21, 31, 41, 51, 61, 71, 81, 92, 2, 12, 22, 32, 42, 52, 62, 72, 82, 93, 3, 13, 23, 33, 43, 53, 63, 73, 83, 94, 4, 14, 24, 34, 44, 54, 64, 74, 84, 95, 5, 15, 25, 35, 45, 55, 65, 75, 85, 96, 6, 16, 26, 36, 46, 56, 66, 76, 86, 97, 7, 17, 27, 37, 47, 57, 67
Offset: 1

Views

Author

Kazimierz Kurz (kurzk(AT)prokom.pl), Mar 01 2001

Keywords

Links

Crossrefs

Cf. A000027, A087406, A060936, A087407, A087408, A087409, A087075, A087410, A087411.
Cf. A091331, A091332.

Programs

  • Mathematica
    FromDigits /@ Partition[ Flatten[ IntegerDigits[ Table[ n, {n, 1, 77}]]], 2] (* Robert G. Wilson v *)
FromDigits/@Partition[Flatten[IntegerDigits/@Range[100]],2] (* Harvey P. Dale, Feb 13 2025 *)
  • PARI
    {c=0; d=[]; for(n=1, 99, while(#d<2, d=concat(d, digits(c++))); print1(d[1],d[2]", "); d=vecextract(d, "^..2"))} \\ M. F. Hasler, Oct 23 2014

Formula

a(2n-1)*100 + a(2n) = A091332(n); a(2n-1) = floor(A091332(n)/100), a(2n) = (A091332(n) mod 100). - M. F. Hasler, Oct 23 2014

Extensions

More terms from Jason Earls, Mar 24 2001

A091331 Natural numbers written out with their digits grouped in triples (leading zeros omitted).

Original entry on oeis.org

123, 456, 789, 101, 112, 131, 415, 161, 718, 192, 21, 222, 324, 252, 627, 282, 930, 313, 233, 343, 536, 373, 839, 404, 142, 434, 445, 464, 748, 495, 51, 525, 354, 555, 657, 585, 960, 616, 263, 646, 566, 676, 869, 707, 172, 737, 475, 767, 778, 798, 81, 828, 384
Offset: 1

Views

Author

J. Taylor (integersfan(AT)yahoo.com), Mar 01 2004

Keywords

Links

Crossrefs

Cf. A059805, A091332.

Programs

  • Mathematica
    FromDigits/@Partition[Flatten[IntegerDigits/@Range[90]],3] (* Harvey P. Dale, Jun 25 2013 *)
  • PARI
    {c=0;d=[];for(n=1,99,while(#d<3,d=concat(d,digits(c++))); print1(d[1]*100+d[2]*10+d[3]",");d=vecextract(d,"^..3"))} \\ M. F. Hasler, Oct 23 2014

A249182 Proceed counterclockwise on the outer keys of a numeric keypad (i.e., 1,2,3,6,9,8,7,4): first single digits, then concatenate two digits, then three, etc.

Original entry on oeis.org

1, 2, 3, 6, 9, 8, 7, 4, 12, 23, 36, 69, 98, 87, 74, 41, 123, 236, 369, 698, 987, 874, 741, 412, 1236, 2369, 3698, 6987, 9874, 8741, 7412, 4123, 12369, 23698, 36987, 69874, 98741, 87412, 74123, 41236, 123698, 236987, 369874, 698741, 987412, 874123, 741236, 412369
Offset: 1

Views

Author

M. F. Hasler, Oct 23 2014

Keywords

Comments

k-digit terms start at index 8k-7; for example, at index 57, start the 8-digit terms 12369874, 23698741, 36987412, 69874123, 98741236, 87412369, 74123698, 41236987.

Crossrefs

Cf. A059805, A091331, A091332, A249163.

Programs

  • PARI
    d=Vec("12369874");for(L=1,6,for(i=1,#d,print1(concat(vector(L,j,d[(i+j-2)%#d+1]))",")))
Showing 1-3 of 3 results.

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

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