A289172 - OEIS

A289172

Irregular triangle read by rows: row n lists terms m of A038566(n) such that A001221(m) = A051265(n), with a(1) = 1.

1, 1, 2, 3, 2, 3, 4, 5, 6, 3, 5, 7, 2, 4, 5, 7, 8, 3, 7, 9, 6, 10, 5, 7, 11, 6, 10, 12, 3, 5, 9, 11, 13, 14, 15, 6, 10, 12, 14, 15, 5, 7, 11, 13, 17, 6, 10, 12, 14, 15, 18, 3, 7, 9, 11, 13, 17, 19, 10, 20, 15, 21, 6, 10, 12, 14, 15, 18, 20, 21, 22, 5, 7, 11

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OFFSET

1,3

COMMENTS

Consider A051265(n), the largest value of A001221(m) for 1 <= m <= n such that gcd(m, n) = 1 (i.e., m is in the reduced residue system or RRS of n, or m is a totative of n). Row n of this sequence consists of m in RRS(n) such that omega(m) = A051265(n).

LINKS

Michael De Vlieger, Table of n, a(n) for the first 1000 rows, flattened

EXAMPLE

Triangle begins:

n T(n,m) A051265(n)

1: 1 0

2: 1 0

3: 2 1

4: 3 1

5: 2 3 4 1

6: 5 1

7: 6 2

8: 3 5 7 1

9: 2 4 5 7 8 1

10: 3 7 9 1

11: 6 10 2

12: 5 7 11 1

13: 6 10 12 2

14: 3 5 9 11 13 1

15: 14 2

16: 15 2

17: 6 10 12 14 15 2

18: 5 7 11 13 17 1

19: 6 10 12 14 15 18 2

20: 3 7 9 11 13 17 19 1

MATHEMATICA

Table[MaximalBy[#, Last][[All, 1]] &@ Map[{#, PrimeNu@ #} &, Cases[Range[n - 1], k_ /; CoprimeQ[n, k]]] /. {} -> {1}, {n, 30}] // Flatten (* Michael De Vlieger, Aug 11 2017 *)

CROSSREFS

Cf. A001221, A002110, A038566, A048597, A051250, A051265, A051266, A051267, A051268.

Sequence in context: A134986 A336860 A216209 * A215653 A358503 A327666

Adjacent sequences: A289169 A289170 A289171 * A289173 A289174 A289175

KEYWORD

nonn,easy,tabf

AUTHOR

Michael De Vlieger, Aug 11 2017

STATUS

approved