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A233465
Numbers n such that sigma(n) = reversal(2n).
1
1259196, 1473381
OFFSET
1,1
COMMENTS
a(3) > 10^12. - Giovanni Resta, Mar 15 2014
MATHEMATICA
rev[n_] := FromDigits@ Reverse@ IntegerDigits@n; Select[Range[2*10^6], DivisorSigma[1, #] == rev[2*#] &] (* Giovanni Resta, Mar 15 2014 *)
CROSSREFS
KEYWORD
nonn,base,more,bref
AUTHOR
Farideh Firoozbakht, Mar 14 2014
STATUS
approved