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A112484 Array where n-th row contains the primes < n and coprime to n. 5
2, 3, 2, 3, 5, 2, 3, 5, 3, 5, 7, 2, 5, 7, 3, 7, 2, 3, 5, 7, 5, 7, 11, 2, 3, 5, 7, 11, 3, 5, 11, 13, 2, 7, 11, 13, 3, 5, 7, 11, 13, 2, 3, 5, 7, 11, 13, 5, 7, 11, 13, 17, 2, 3, 5, 7, 11, 13, 17, 3, 7, 11, 13, 17, 19, 2, 5, 11, 13, 17, 19, 3, 5, 7, 13, 17, 19, 2, 3, 5, 7, 11, 13, 17, 19, 5, 7, 11, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

Array's n-th row contains A048865(n) terms.

T(A005408(n),1) = 2; T(n,1) = A053669(n). - Reinhard Zumkeller, Sep 23 2011

These are the primes in row n >= 3 of A038566 (smallest positive restricted residue system modulo n). - Wolfdieter Lang, Jan 18 2017

LINKS

Michael De Vlieger, Table of n, a(n) for n = 3..16603 (rows 3 <= n <= 400).

EXAMPLE

Row 9 is [2, 5, 7], since 2, 5 and 7 are the primes < 9 and coprime to 9.

The irregular triangle begins:

n\k 1 2  3  4  5  6  7  8 ...

3:  2

4:  3

5:  2 3

6:  5

7:  2 3  5

8:  3 5  7

9:  2 5  7

10: 3 7

11: 2 3  5  7

12: 5 7 11

13: 2 3  5  7 11

14: 3 5 11 13

15: 2 7 11 13

16: 3 5  7 11 13

17: 2 3  5  7 11 13

18: 5 7 11 13 17

19: 2 3  5  7 11 13 17

20: 3 7 11 13 17 19

21: 2 5 11 13 17 19

22: 3 5  7 13 17 19

23: 2 3  5  7 11 13 17 19

... - Wolfdieter Lang, Jan 18 2017

MATHEMATICA

f[l_] := Block[{n}, n = Length[l] + 1; Return[Append[l, Select[Range[n - 1], PrimeQ[ # ] && Mod[n, # ] > 0 &]]]; ]; Flatten[Nest[f, {}, 24]] (* Ray Chandler, Dec 26 2005 *)

Table[Complement[Prime@ Range@ PrimePi@ n, FactorInteger[n][[All, 1]]], {n, 3, 23}] // Flatten (* Michael De Vlieger, Sep 04 2017 *)

PROG

(Python)

from sympy import primerange, gcd

def a(n): return list(filter(lambda i: gcd(i, n)==1, primerange(1, n)))

for n in range(3, 24): print a(n) # Indranil Ghosh, Apr 27 2017

CROSSREFS

Cf. A038566, A048865, A053669.

Sequence in context: A114868 A249049 A138239 * A174063 A327277 A124459

Adjacent sequences:  A112481 A112482 A112483 * A112485 A112486 A112487

KEYWORD

nonn,tabf

AUTHOR

Leroy Quet, Dec 13 2005

EXTENSIONS

Extended by Ray Chandler, Dec 26 2005

STATUS

approved

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Last modified April 10 22:29 EDT 2021. Contains 342856 sequences. (Running on oeis4.)