login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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. 3
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:

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

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 A080997 A151942

Adjacent sequences:  A224528 A224529 A224530 * A224532 A224533 A224534

KEYWORD

nonn,tabl

AUTHOR

T. D. Noe, Apr 11 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 29 16:13 EDT 2020. Contains 337432 sequences. (Running on oeis4.)