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A374377
Least n-digit reversible prime whose difference from its reversal is maximal.
1
2, 17, 149, 1069, 10499, 101999, 1013899, 10012999, 100148999, 1000009999, 10000099999, 100009799999, 1000000999999, 10000069999999, 100001386999999, 1000001939999999, 10000004099999999, 100000001599999999, 1000000073599999999
OFFSET
1,1
COMMENTS
Inspired by A374350.
EXAMPLE
Although the primes {149, 179, 199, 941, 971, 991} all have prime reversals and their differences are 792, 149 is the least. Therefore a(3) = 149.
MATHEMATICA
a[n_] := Block[{lmt = 2*10^(n -1) +1, mx = 0, p = NextPrime[10^(n -1)], q}, While[p < lmt, q = IntegerReverse@ p; If[ PrimeQ@ q && Abs[p -q] > mx, mx = Abs[p -q]; pq = p]; p = NextPrime@ p]; pq];
CROSSREFS
Cf. A374350.
Sequence in context: A110815 A273340 A074624 * A245807 A295946 A176934
KEYWORD
base,nonn,more
AUTHOR
Robert G. Wilson v, Jul 06 2024
STATUS
approved