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 1-6 of 6 results.

A139419 a(n) = first term of the n-th run of consecutive numbers in A136120.

Original entry on oeis.org

1, 3, 9, 15, 22, 36, 48, 69, 87, 116, 141, 167, 194, 222, 269, 308, 368, 419, 471, 524, 578, 633, 719, 791, 896, 986, 1077, 1169, 1262, 1356, 1451, 1591, 1710, 1876, 2020, 2213, 2383, 2604, 2801, 3051, 3276, 3502, 3729, 3957, 4186, 4416, 4647, 4879, 5112
Offset: 1

Views

Author

Klaus Brockhaus, Apr 22 2008

Keywords

Examples

			A136120 starts 1, 3, 4, 5, 9, 10, 15, ..., so a(1) = 1, a(2) = 3, a(3) = 9.
		

Crossrefs

Programs

  • Mathematica
    f[seq_] := Module[{s = seq, n1, n2}, n++; n1 = s[[n]] + n; If[n1 <= len, n2 = Min[n - 1 + 2*s[[n]], len]; len -= n2 - n1 + 1; Drop[s, {n1, n2}], s]]; n = 0; len = 5200; First /@Split[FixedPoint[f, Range[len]], #2 - #1 == 1 &] (* Jayanta Basu, Jun 15 2013 - using the Mma program in A136120 *)

A139420 a(n) = length of n-th run of consecutive numbers in A136120.

Original entry on oeis.org

1, 3, 2, 2, 5, 2, 6, 2, 7, 2, 2, 2, 2, 11, 2, 12, 2, 2, 2, 2, 2, 17, 2, 18, 2, 2, 2, 2, 2, 2, 24, 2, 25, 2, 26, 2, 27, 2, 28, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 38, 2, 39, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 50, 2, 51, 2, 52, 2, 53, 2, 54, 2, 55, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 71, 2, 72, 2, 2, 2
Offset: 1

Views

Author

Klaus Brockhaus, Apr 22 2008

Keywords

Examples

			A136120 starts 1, 3, 4, 5, 9, 10, 15, ..., so a(1) = 1, a(2) = 3, a(3) = 2.
		

Crossrefs

Programs

  • Mathematica
    f[seq_] := Module[{s = seq, n1, n2}, n++; n1 = s[[n]] + n; If[n1 <= len, n2 = Min[n - 1 + 2*s[[n]], len]; len -= n2 - n1 + 1; Drop[s, {n1, n2}], s]]; n = 0; len = 29800; Length /@Split[FixedPoint[f, Range[len]], #2 - #1 == 1 &]  (* Jayanta Basu, Jun 15 2013 - using the Mma program in A136120 *)

A139418 Complement of A136120.

Original entry on oeis.org

2, 6, 7, 8, 11, 12, 13, 14, 17, 18, 19, 20, 21, 27, 28, 29, 30, 31, 32, 33, 34, 35, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 94, 95, 96, 97, 98, 99, 100, 101
Offset: 1

Views

Author

Klaus Brockhaus, Apr 22 2008

Keywords

Comments

k-th run of consecutive numbers has length A136120(k).

Examples

			A136120 starts 1, 3, 4, 5, 9, 10, 15, ..., so sequence starts 2, 6, 7, 8, 11, 12, ... .
		

Crossrefs

A137832 Limiting sequence when we start with the positive integers (A000027) and delete in step n >= 1 the last digit in the term at position n + a(n).

Original entry on oeis.org

1, 3, 4, 5, 7, 8, 10, 11, 1, 1, 1, 16, 1, 1, 1, 21, 2, 23, 2, 25, 2, 27, 2, 29, 3, 31, 3, 3, 34, 3, 3, 37, 3, 3, 40, 4, 43, 44, 45, 47, 48, 49, 5, 51, 52, 53, 5, 5, 56, 57, 5, 5, 6, 61, 6, 6, 6, 65, 6, 67, 69, 7, 7, 72, 7, 7, 75, 76, 7, 7, 79, 8, 82, 83, 84, 8
Offset: 1

Views

Author

Ctibor O. Zizka, Apr 29 2008

Keywords

Examples

			First few steps are:
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,...
n = 1; delete the last digit in the term at position 1+a(1) = 2: 2;
1,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,...
n = 2; delete the last digit in the term at position 2+a(2) = 5: 6;
1,3,4,5,7,8,9,10,11,12,13,14,15,16,17,18,19,20,...
n = 3; delete the last digit in the term at position 3+a(3) = 7: 9;
1,3,4,5,7,8,10,11,12,13,14,15,16,17,18,19,20,...
n = 4; delete the last digit in the term at position 4+a(4) = 9: 2;
1,3,4,5,7,8,10,11,1,13,14,15,16,17,18,19,20,...
n = 5; delete the last digit in the term at position 5+a(5) = 12: 5;
1,3,4,5,7,8,10,11,1,13,14,1,16,17,18,19,20,...
n = 6; delete the last digit in the term at position 6+a(6) = 14: 8;
1,3,4,5,7,8,10,11,1,13,14,1,16,17,1,19,20,...
		

Crossrefs

A137838 Limiting sequence when we start with the positive integers (A000027) and delete in step n >= 1 the first digit in the term at position n + a(n).

Original entry on oeis.org

1, 3, 4, 5, 7, 8, 10, 11, 2, 13, 4, 5, 16, 7, 8, 19, 21, 2, 23, 4, 5, 6, 7, 8, 29, 0
Offset: 1

Views

Author

Ctibor O. Zizka, Apr 29 2008

Keywords

Examples

			First few steps are:
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,...
n = 1; delete the first digit in the term at position 1+a(1) = 2: 2;
1,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,...
n = 2; delete the first digit in the term at position 2+a(2) = 5: 6;
1,3,4,5,7,8,9,10,11,12,13,14,15,16,17,18,19,20,...
n = 3; delete the first digit in the term at position 3+a(3) = 7: 9;
1,3,4,5,7,8,10,11,12,13,14,15,16,17,18,19,20,...
n = 4; delete the first digit in the term at position 4+a(4) = 9: 1;
1,3,4,5,7,8,10,11,2,13,14,15,16,17,18,19,20,...
n = 5; delete the first digit in the term at position 5+a(5) = 12: 1;
1,3,4,5,7,8,10,11,2,13,14,5,16,17,18,19,20,...
n = 6; delete the first digit in the term at position 6+a(6) = 14: 1;
1,3,4,5,7,8,10,11,2,13,14,5,16,7,18,19,20,...
		

Crossrefs

A138095 Limiting sequence when we start with positive integers (A000027) and at step n >= 1 add: to the term at position n + 1*a(n) the value 1, to the term at position n + 2*a(n) the value 1, ..., to the term at position n + n*a(n) the value 1.

Original entry on oeis.org

1, 3, 3, 4, 6, 7, 7, 10, 10, 10, 12, 14, 14, 15, 15, 17, 18, 19, 20, 23, 22, 22, 25, 24, 25, 27, 29, 30, 32, 32, 31, 32, 34, 35, 39, 36, 38, 39, 41, 42, 43, 43, 45, 46, 46, 46, 48, 52, 51, 53, 51, 52, 55, 55, 56, 59, 57, 60, 63, 62, 62, 64, 63, 65, 66, 68, 69, 70, 72, 71
Offset: 1

Views

Author

Ctibor O. Zizka, May 03 2008

Keywords

Examples

			        n | 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20
  --------+-----------------------------------------------------------
  Step  1 |    3
  Step  2 |             6        9
  Step  3 |                7       10       13
  Step  4 |                     10          14          17          21
  Step  5 |                              12                18
  Step  6 |                                    14                   22
  Step  7 |                                       15
  Step  8 |                                                   19
  Step  9 |                                                      20
  Step 10 |                                                         23
  --------+-----------------------------------------------------------
     a(n) | 1  3  3  4  6  7  7 10 10 10 12 14 14 15 15 17 18 19 20 23
		

Crossrefs

Programs

  • PARI
    lista(nn) = my(va = [1..nn]); for (n=1, nn, for (k=1, n, my(j = n+k*va[n]); if (j <= #va, va[j]++); )); va; \\ Michel Marcus, Aug 09 2022

Extensions

Corrected and extended by Michel Marcus, Aug 09 2022
Showing 1-6 of 6 results.