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 1-4 of 4 results.

A095167 Triangle read by rows in which the n-th row contains n numbers noncoprime to n and not occurring in earlier rows.

Original entry on oeis.org

1, 2, 4, 3, 6, 9, 8, 10, 12, 14, 5, 15, 20, 25, 30, 16, 18, 21, 22, 24, 26, 7, 28, 35, 42, 49, 56, 63, 32, 34, 36, 38, 40, 44, 46, 48, 27, 33, 39, 45, 51, 54, 57, 60, 66, 50, 52, 55, 58, 62, 64, 65, 68, 70, 72, 11, 77, 88, 99, 110, 121, 132, 143, 154, 165, 176, 69, 74, 75, 76
Offset: 1

Views

Author

Amarnath Murthy, Jun 01 2004

Keywords

Comments

Rearrangement of natural numbers so that next n numbers are not coprime to n.

Examples

			1
2 4
3 6 9
8 10 12 14
5 15 20 25 30
16 18 21 22 24 26
7 28 35 42 49 56 63
...

Links

Crossrefs

Cf. A095168, A095169, A095170, A095171.
Cf. A081964 (coprime instead of non-coprime).

Programs

  • Mathematica
    Fold[Function[{a, n}, Join[a, Select[Complement[Range[Max[a] + n^2], a], GCD[n, #] > 1 &, n]]], {1}, Range[2, 12]] (* Ivan Neretin, Jun 05 2015 *)
  • PARI
    S=Set();for(n=2,20,k=0;m=1;while(k1,S=setunion(S,[m]);print1(" ",m);k++))) (Alekseyev)

Extensions

More terms from Max Alekseyev, Jun 30 2005

A095169 Leading diagonal of the triangle A095167.

Original entry on oeis.org

1, 4, 9, 14, 30, 26, 63, 48, 66, 72, 176, 90, 247, 119, 144, 168, 425, 198, 551, 230, 270, 290, 828, 327, 445, 394, 474, 470, 1305, 519, 1426, 592, 636, 680, 749, 756, 2072, 838, 903, 926, 2624, 978, 2881, 1058, 1130, 1194, 3337, 1266, 1582, 1356
Offset: 1

Views

Author

Amarnath Murthy, Jun 01 2004

Keywords

Crossrefs

Cf. A095167, A095168, A095170, A095171.

Programs

  • PARI
    S=Set(); for(n=2,20, k=0; m=1; while(k1, S=setunion(S,[m]); k++) ); print1(" ",m) ) (Alekseyev)

Extensions

More terms from Max Alekseyev, Jun 30 2005

A095170 Row sums of A095167.

Original entry on oeis.org

1, 6, 18, 44, 95, 127, 280, 318, 432, 616, 1276, 962, 2067, 1480, 1820, 2360, 4709, 3258, 6802, 4105, 4943, 5818, 12719, 7345, 9235, 9398, 11373, 11675, 25201, 14899, 28458, 17828, 18882, 21879, 23246, 25703, 50283, 30272, 31983, 35175, 71668
Offset: 1

Views

Author

Amarnath Murthy, Jun 01 2004

Keywords

Crossrefs

Cf. A095167, A095168, A095169, A095171.

Programs

  • PARI
    S=Set();for(n=2,50,k=0;m=1;s=0;while(k1,S=setunion(S,[m]);k++;s+=m));print1(" ",s)) (Alekseyev)

Extensions

More terms from Max Alekseyev, Jun 30 2005

A095171 Number of multiples of n in the n-th row of the triangle A095167.

Original entry on oeis.org

1, 2, 3, 2, 5, 2, 7, 3, 3, 2, 11, 1, 13, 2, 2, 2, 17, 2, 19, 2, 2, 2, 23, 1, 4, 2, 2, 1, 29, 2, 31, 2, 3, 2, 3, 2, 37, 3, 3, 2, 41, 1, 43, 2, 3, 1, 47, 2, 8, 2, 2, 1, 53, 1, 4, 2, 3, 3, 59, 2, 61, 2, 3, 3, 3, 1, 67, 2, 2, 2, 71, 1, 73, 3, 2, 1, 3, 1, 79, 1, 3, 2, 83, 1, 4, 2, 1, 3, 89, 1, 5, 1, 3, 2, 3, 2
Offset: 1

Views

Author

Amarnath Murthy, Jun 01 2004

Keywords

Comments

a(p) = p if p is a prime. a(4) = 2 as among 8, 10,12,14, there are two multiples of 4.

Crossrefs

Cf. A095167, A095168, A095169, A095170.

Programs

  • PARI
    S=Set();for(n=2,100,k=0;m=1;s=0;while(k1,S=setunion(S,[m]);k++;if(m%n==0,s++)));print1(" ",s)) (Alekseyev)

Extensions

More terms from Max Alekseyev, Jun 30 2005
Showing 1-4 of 4 results.

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

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