A087305 Smallest n-digit non-palindromic number such that it and its digit reversal have the same prime signature.
13, 107, 1002, 10002, 100006, 1000007, 10000013, 100000005, 1000000007, 10000000006, 100000000007, 1000000000006, 10000000000003, 100000000000002, 1000000000000003, 10000000000000002, 100000000000000005, 1000000000000000005, 10000000000000000021, 100000000000000000031
Offset: 2
Examples
a(6) = 100006 = 2*13*1613 and 600001 = 19*23*1373 both have prime signature p*q*r, p,q,r are primes.
Programs
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PARI
rev(n) = fromdigits(Vecrev(digits(n))); psig(n) = vecsort(factor(n)[,2]~); a(n) = {my(k = 10^n+1); while(k == rev(k) || psig(k) != psig(rev(k)), k++); k;} \\ Amiram Eldar, May 19 2024
Extensions
More terms from David Wasserman, Apr 19 2005
More terms from Amiram Eldar, May 19 2024