A224531 -id:A224531

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A224532

Largest number k such that phi(k) = A007374(n).

+10
3

2, 6, 12, 30, 42, 120, 126, 150, 90, 210, 660, 1242, 7938, 2760, 1014, 270, 1470, 810, 3318, 630, 2370, 4830, 7590, 1386, 11220, 1680, 1260, 5082, 13890, 1050, 3570, 33750, 1890, 26082, 14058, 2310, 2730, 5670, 5250, 70140, 12690, 14280, 12474, 3990, 11850

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

OFFSET

2,1

COMMENTS

That is, the largest number k such that phi(k) = x, with x being the least number having n solutions. - T. D. Noe, Apr 14 2013

LINKS

T. D. Noe, Table of n, a(n) for n = 2..1023

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

MATHEMATICA

Needs["CNT`"]; nn = 50; t = Table[0, {nn}]; n = 0; left = nn - 1; While[left > 0, n++; cnt = Length[PhiInverse[n]]; If[cnt <= nn && t[[cnt]] == 0, t[[cnt]] = n; left--]]; Join[{0}, Table[PhiInverse[n][[-1]], {n, Rest[t]}]]

CROSSREFS

Cf. A224531.

KEYWORD

nonn

AUTHOR

T. D. Noe, Apr 11 2013

STATUS

approved

A066420

Least m such that card(invphi(phi(m)))=n.

+10
2

1, 3, 5, 15, 13, 51, 37, 41, 35, 65, 187, 397, 2269, 1059, 313, 73, 337, 247, 937, 185, 689, 1139, 2057, 403, 2827, 485, 323, 1321, 3697, 241, 769, 9001, 433, 7129, 4201, 527, 577, 1297, 1201, 15937, 3313, 3281, 3379, 949, 3121, 7519, 3889, 779, 1763

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

OFFSET

2,2

LINKS

T. D. Noe, Table of n, a(n) for n = 2..1023

FORMULA

a(n) = A049283(A007374(n)). - Max Alekseyev, Apr 12 2005

CROSSREFS

Cf. A049283, A007374.

Cf. A224531, A224532.

KEYWORD

nonn