A071389 Least number m such that cardinality of InvPhi[m] = prime(n).

1, 2, 8, 32, 48, 396, 72, 216, 1056, 1320, 240, 480, 15936, 3072, 7344, 2016, 3024, 9984, 22848, 3360, 13248, 9360, 4800, 9504, 9216, 23328, 7680, 53280, 12480, 29376, 91200, 159744, 22464, 228960, 29952, 179200, 47040, 68544, 15840, 20736, 61440

Offset

1,2

Links

Table of n, a(n) for n=1..41.

Formula

a(n)=Min{x; Card[InvPhi[x]]=p(n), n-th prime}

Example

n=11: p(11)=31, Card[InvPhi[x]]=31 for {240,672,...}; the smallest is 240 = a(11).

Crossrefs

Cf. A000010, A014197, A058277, A063512, A071386-A071388.

Sequence in context: A330782 A200063 A238984 * A026369 A269818 A331823

Adjacent sequences: A071386 A071387 A071388 * A071390 A071391 A071392

Keyword

nonn

Author

Labos Elemer, May 23 2002

Extensions

4 more terms from Emeric Deutsch, Jul 25 2005

More terms from Max Alekseyev, Apr 24 2010

Status

approved