OFFSET
1,1
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..1054
EXAMPLE
341 is in the sequence because 341 = 11 * 31, which is semiprime, and reversal(341) + 1 = 143 + 1 = 144 = 12^2.
591 is in the sequence because 591 = 3 * 197, which is semiprime, and reversal(591) + 1 = 195 + 1 = 196 = 14^2.
MATHEMATICA
Select[Range[10^5], PrimeOmega[#] == 2 && IntegerQ[Sqrt[FromDigits[Reverse[IntegerDigits[#]]] + 1]] &]
PROG
(PARI)
revint(n) = eval(concat(Vecrev(Str(n))))
select(n->bigomega(n)==2 && issquare(revint(n)+1), vector(100000, n, n)) \\ Colin Barker, Jul 20 2014
CROSSREFS
KEYWORD
nonn,base
AUTHOR
K. D. Bajpai, Jul 18 2014
STATUS
approved