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 A183147 1 together with the numbers with property that at least two successive of their divisors are odd or even. 1
 1, 3, 4, 5, 7, 8, 9, 11, 12, 13, 15, 16, 17, 19, 20, 21, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 39, 40, 41, 43, 44, 45, 47, 48, 49, 51, 52, 53, 55, 56, 57, 59, 60, 61, 63, 64, 65, 67, 68, 69, 70, 71, 72, 73, 75, 76, 77, 79, 80, 81, 83, 84, 85, 87, 88, 89, 90, 91, 92, 93, 95, 96, 97, 99, 100 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Wikipedia, Table of divisors EXAMPLE 12 is in the sequence because its divisors are 1, 2, 3, 4, 6, 12 and then we can see that the successive divisors 4, 6, and 12 are even numbers. MAPLE isA183147 := proc(n)         local di, i ;         if n = 1 then                 return true;         end if;         di := sort(convert(numtheory[divisors](n), list)) ;         for i from 1 to nops(di)-1 do                 if (op(i+1, di)-op(i, di)) mod 2 = 0 then                         return true;                 end if;         end do;         return false; end proc: for n from 1 to 100 do         if isA183147(n) then                 printf("%d, ", n);         end if; end do; # R. J. Mathar, Sep 30 2011 CROSSREFS Complement of A182991, for n > 1. Cf. A182996. Sequence in context: A285958 A179779 A284679 * A074227 A122906 A042965 Adjacent sequences:  A183144 A183145 A183146 * A183148 A183149 A183150 KEYWORD nonn,easy AUTHOR Omar E. Pol, Aug 04 2011 STATUS approved

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Last modified February 19 22:04 EST 2020. Contains 332060 sequences. (Running on oeis4.)