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Search: id:A036431
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%I A036431
%S A036431 0,1,0,1,1,0,2,0,1,1,0,2,1,1,1,0,0,2,2,0,2,0,0,1,2,2,0,1,0,1,2,1,1,1,0,
%T A036431 0,1,3,2,0,0,1,2,0,2,0,0,1,1,3,1,1,0,0,2,1,0,2,1,0,2,2,1,1,0,1,0,0,3,0,
%U A036431 1,1,2,2,1,0,0,2,0,0,3,1,0,1,1,3,3,0,0,1,2,2,0,0,0,1,2,1,2,2
%N A036431 a(n) = number of positive integers b which, when added to the number 
               of their divisors, tau(b), gives n.
%C A036431 Invented by the HR concept formation program.
%H A036431 S. Colton, <a href="http://www.cs.uwaterloo.ca/journals/JIS/index.html">
               Refactorable Numbers - A Machine Invention</a>, J. Integer Sequences, 
               Vol. 2, 1999, #2.
%H A036431 S. Colton, <a href="http://www.dai.ed.ac.uk/homes/simonco/research/hr/
               ">HR - Automatic Theory Formation in Pure Mathematics</a>
%F A036431 a(n) = |{b in N : b + tau(b) = n}|
%e A036431 a(7) = 2 because (i) 4+tau(4)=7 and (ii) 5+tau(5)=7.
%Y A036431 Cf. A036432.
%Y A036431 Sequence in context: A140080 A065359 A087372 this_sequence A029407 A099544 
               A036414
%Y A036431 Adjacent sequences: A036428 A036429 A036430 this_sequence A036432 A036433 
               A036434
%K A036431 nonn
%O A036431 0,7
%A A036431 Simon Colton (simonco(AT)cs.york.ac.uk)

    
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Last modified December 8 08:31 EST 2009. Contains 170430 sequences.


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