COMMENT FROM M. F. Hasler RE A037916

[Maximilian Hasler]

%I A037916
%S A037916 0, 1, 1, 2, 1, 11, 1, 3, 2, 11, 1, 12, 1, 11, 11, 4, 1, 12,
1, 12, 11, 11, 1, 13, 2, 11, 3, 12, 1, 111, 1, 5, 11, 11, 11, 22, 1,
11, 11, 13, 1, 111, 1, 12, 12, 11, 1, 14, 2, 12, 11, 12, 1, 13, 11,
13, 11, 11, 1, 112, 1, 11, 12, 6, 11, 111, 1, 12, 11, 111, 1, 23, 1,
11, 12, 12, 11, 111, 1, 14, 4, 11, 1, 112, 11, 11, 11, 13, 1, 112, 11,
12, 11, 11, 11, 15, 1, 12, 12
%N A037916 Sum( e[i] 10^(m-i), i=1..m ) where e[1]<=...<=e[m] are the
nonzero exponents in the prime factorization of n: a representation of
the prime signature of n.
%C A139393 The sorted sequence of (nonzero) exponents in the prime
factorization of a number is called its prime signature. Here this is
"approximated" by multiplying them by powers of 10. Up to 2^10 this
coincides with the concatenation of these exponents written in base 10
(but that sequence would be "base" specific). For n>=1024 one should
use a modified definition, replacing 10 by 10^floor(log2(n)/10), to
avoid ambiguity of the representation.
%H A139393 Wikipedia, <a href="http://en.wikipedia.org/wiki/Prime_signature">
  Prime signature</a>.
%H A139393 E.W.Weisstein, <a
href="http://mathworld.wolfram.com/PrimeSignature.html">Prime
signature</a> on mathworld.wolfram.com.
%o A139393 (PARI) A139393(n)=sum(i=1,#n=vecsort(factor(n)[,2]),10^(#n-i)*n[i])
%K A139393 nonn,easy
%O A139393 1,4
%A A139393 M. F. Hasler (www.univ-ag.fr/~mhasler), Apr 17 2008