A224531 - OEIS

A224531

Triangle in which row n > 1 has the n values x such that phi(x) = A007374(n), We define the first row to be 0.

0, 1, 2, 3, 4, 6, 5, 8, 10, 12, 15, 16, 20, 24, 30, 13, 21, 26, 28, 36, 42, 51, 64, 68, 80, 96, 102, 120, 37, 57, 63, 74, 76, 108, 114, 126, 41, 55, 75, 82, 88, 100, 110, 132, 150, 35, 39, 45, 52, 56, 70, 72, 78, 84, 90, 65, 104, 105, 112, 130, 140, 144, 156, 168, 180, 210

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

T. D. Noe, Rows n = 1..100 of triangle, flattened

D. Bressoud, CNT.m Computational Number Theory Mathematica package.

EXAMPLE

Triangle:

1, 2,

3, 4, 6,

5, 8, 10, 12,

15, 16, 20, 24, 30,

13, 21, 26, 28, 36, 42,

51, 64, 68, 80, 96, 102, 120,

37, 57, 63, 74, 76, 108, 114, 126,

41, 55, 75, 82, 88, 100, 110, 132, 150

MATHEMATICA

Needs["CNT`"]; nn = 10; t = Table[{}, {nn}]; n = 0; t[[1]] = {0}; left = nn - 1; While[left > 0, n++; p = PhiInverse[n]; cnt = Length[p]; If[cnt <= nn && t[[cnt]] == {}, t[[cnt]] = p; left--]]; t

CROSSREFS

Cf. A066420, A224532 (numbers in the first column and diagonal).

Sequence in context: A197756 A080738 A032447 * A058213 A348711 A080997

Adjacent sequences: A224528 A224529 A224530 * A224532 A224533 A224534

KEYWORD

nonn,tabl

AUTHOR

T. D. Noe, Apr 11 2013

STATUS

approved