

A087305


Smallest ndigit nonpalindromic number such that it and its digit reversal have the same prime signature.


0



13, 107, 1002, 10002, 100006, 1000007, 10000013, 100000005, 1000000007, 10000000006, 100000000007, 1000000000006, 10000000000003, 100000000000002, 1000000000000003, 10000000000000002, 100000000000000005, 1000000000000000005, 10000000000000000021, 100000000000000000031
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

2,1


LINKS



EXAMPLE

a(6) = 100006 = 2*13*1613 and 600001 = 19*23*1373 both have prime signature p*q*r, p,q,r are primes.


PROG

(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


CROSSREFS



KEYWORD

base,nonn,changed


AUTHOR



EXTENSIONS



STATUS

approved



