

A053212


Number of divisors of the minimal numbers (A007416).


5



1, 2, 3, 4, 6, 5, 8, 9, 10, 12, 7, 16, 15, 18, 14, 20, 24, 21, 30, 32, 27, 28, 11, 36, 25, 40, 48, 42, 22, 45, 13, 60, 35, 54, 50, 56, 64, 33, 72, 26, 63, 80, 44, 84, 90, 70, 96, 75, 39, 81, 100, 66, 49, 108, 120, 112, 52, 17, 55, 128, 126, 88, 144, 105, 160
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OFFSET

1,2


COMMENTS

A permutation of the natural numbers.


LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000
Index entries for sequences that are permutations of the natural numbers


FORMULA

a(n) = A000005(A007416(n)).  Omar E. Pol, Dec 26 2008


MATHEMATICA

Reap[For[n = 1, n <= 10^5, n++, tau = DivisorSigma[0, n]; If[Abs[Product[DivisorSigma[0, k]  tau, {k, 1, n  1}]] > 0, Print[tau]; Sow[tau]]]][[2, 1]] (* JeanFrançois Alcover, Jan 16 2013 *)


PROG

(Haskell)
a053212 = a000005' . a007416  Reinhard Zumkeller, Apr 18 2015


CROSSREFS

Cf. A007416, A005179. Inverse permutation to A064787.
Cf. A000005.  Omar E. Pol, Dec 26 2008
Sequence in context: A263265 A263267 A257471 * A095424 A194507 A118316
Adjacent sequences: A053209 A053210 A053211 * A053213 A053214 A053215


KEYWORD

nonn,nice


AUTHOR

Asher Auel (asher.auel(AT)reed.edu) Dec 16, 1999


EXTENSIONS

More terms from Naohiro Nomoto, Apr 03 2001


STATUS

approved



