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A073916
The n-th number with n divisors.
2
1, 3, 25, 14, 14641, 44, 24137569, 70, 1089, 405, 819628286980801, 160, 22563490300366186081, 2752, 9801, 462, 21559177407076402401757871041, 1044, 740195513856780056217081017732809, 1520, 141376, 84992
OFFSET
1,2
COMMENTS
Last element in n-th row of A073915.
a(p) = prime(p)^(p-1) for any prime number p. - Paul Tek, Jun 23 2013
EXAMPLE
For n = 4; the numbers with four divisors are 6, 8, 10, 14, 15, 21,... so a(4) = 14 because 14 is the 4th number with four divisors. - Omar E. Pol, Jun 01 2012
MATHEMATICA
d = Table[Length[Divisors[n]], {n, 200000}]; t = {}; n = 0; ok = True; While[ok, n++; If[PrimeQ[n], AppendTo[t, Prime[n]^(n - 1)], c = Flatten[Position[d, n, 1, n]]; If[Length[c] >= n, AppendTo[t, c[[n]]], ok = False]]]; t (* T. D. Noe, Jun 23 2013 *)
CROSSREFS
Cf. A073915.
Sequence in context: A234319 A224873 A085836 * A076962 A370416 A304480
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Aug 18 2002
EXTENSIONS
More terms from Sascha Kurz, Jan 28 2003
New name from Omar E. Pol, Jun 01 2012
a(22)-a(34) from Paul Tek, Jun 23 2013
STATUS
approved