A374377 Least n-digit reversible prime whose difference from its reversal is maximal.

2, 17, 149, 1069, 10499, 101999, 1013899, 10012999, 100148999, 1000009999, 10000099999, 100009799999, 1000000999999, 10000069999999, 100001386999999, 1000001939999999, 10000004099999999, 100000001599999999, 1000000073599999999

Offset: 1

Author

Robert G. Wilson v, Jul 06 2024

Keywords

• base
• nonn
• more

Comments

Inspired by A374350.

Examples

			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.
		

Crossrefs

Cf. A374350.

Programs

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];