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A181687 Numbers n such that the number of odd divisors of (2n)^2 is an odd divisor of (2n)^2, and the number of even divisors of (2n)^2 is an even divisor of (2n)^2. 1
1, 2, 3, 6, 8, 12, 15, 21, 24, 25, 30, 33, 39, 42, 45, 50, 51, 57, 66, 69, 75, 78, 81, 87, 90, 93, 96, 102, 111, 114, 120, 123, 128, 129, 138, 141, 150, 159, 162, 168, 174, 177, 180, 183, 186, 189, 200, 201, 213, 219, 222, 225, 237, 240, 246, 249, 258, 264, 267, 282, 291, 300 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A016742(a(n)) = A181795(n)

LINKS

Table of n, a(n) for n=1..62.

MAPLE

for j from 1 to 300 do

   y:=(2*j)^2:evdiv:=0:oddiv:=0:

   for k in divisors(y) do

      if(k mod 2=0)then evdiv:=evdiv+1:else oddiv:=oddiv+1:fi:

   od:

   if(type(y/evdiv, integer) and type(y/oddiv, integer))then

      print(j);

   fi;

od:

CROSSREFS

Sequence in context: A198442 A035106 A122378 * A194881 A111242 A133582

Adjacent sequences:  A181684 A181685 A181686 * A181688 A181689 A181690

KEYWORD

easy,nonn

AUTHOR

Nathaniel Johnston, Nov 17 2010

STATUS

approved

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Last modified September 23 13:34 EDT 2020. Contains 337310 sequences. (Running on oeis4.)