|
| |
|
|
A097942
|
|
Highly totient numbers: each number k on this list has more solutions to the equation phi(x) = k than any preceding k (where phi is Euler's totient function, A000010).
|
|
8
| |
|
|
1, 2, 4, 8, 12, 24, 48, 72, 144, 240, 432, 480, 576, 720, 1152, 1440, 2880, 4320, 5760, 8640, 11520, 17280, 25920, 30240, 34560, 40320, 51840, 60480, 69120, 80640, 103680, 120960, 161280, 181440, 207360, 241920, 362880, 483840, 725760, 967680
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| If you inspect PhiAnsYldList after running the program below, the zeros with even-numbered indices should correspond to the nontotients (A005277).
Where records occur in A014197. - T. D. Noe (noe(AT)sspectra.com), Jun 13 2006. Cf. A131934.
|
|
|
LINKS
| T. D. Noe, Table of n, a(n) for n=1..79
Wikipedia, Highly totient number
|
|
|
EXAMPLE
| a(4) = 8 since phi(x) = 8 has the solutions {15, 16, 20, 24, 30}, one more solution than a(3) = 4 for which phi(x) = 4 has solutions {5, 8, 10, 12}.
|
|
|
MATHEMATICA
| searchMax = 2000; phiAnsYldList = Table[0, {searchMax}]; Do[phiAns = EulerPhi[m]; If[phiAns <= searchMax, phiAnsYldList[[phiAns]]++ ], {m, 1, searchMax^2}]; highlyTotientList = {1}; currHigh = 1; Do[If[phiAnsYldList[[n]] > phiAnsYldList[[currHigh]], highlyTotientList = {highlyTotientList, n}; currHigh = n], {n, 2, searchMax}]; Flatten[highlyTotientList]
|
|
|
CROSSREFS
| A subsequence of A007374.
Cf. A000010, A005277, A014573, A004653, A105207, A105208.
Sequence in context: A171647 A089821 A181808 * A004653 A115386 A058771
Adjacent sequences: A097939 A097940 A097941 * A097943 A097944 A097945
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Alonso Delarte (alonso.delarte(AT)gmail.com), Sep 05 2004
|
|
|
EXTENSIONS
| Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 07 2004
|
| |
|
|
