OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harvey P. Dale)
EXAMPLE
a(1) = 21 because 21 is a deficient number whose reversal, 12, is an abundant number.
MATHEMATICA
dnanQ[n_]:=Module[{rev=FromDigits[Reverse[IntegerDigits[n]]]}, DivisorSigma[ 1, n]<2n&&DivisorSigma[1, rev]>2rev]; Select[Range[500], dnanQ] (* Harvey P. Dale, Apr 06 2013 *)
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Shyam Sunder Gupta, Oct 02 2004
STATUS
approved