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

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

Author

Amarnath Murthy, Jun 01 2004

Keywords

• nonn
• tabl

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

• Ivan Neretin, Rows n = 1..141, flattened

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