A354881 Primes p such that, if q is the next prime, the digit reversal of p*q is prime.

5, 31, 37, 41, 53, 103, 197, 263, 277, 337, 349, 353, 359, 373, 397, 401, 421, 431, 439, 547, 569, 587, 599, 857, 859, 863, 877, 883, 983, 1009, 1013, 1039, 1069, 1091, 1097, 1103, 1117, 1129, 1153, 1171, 1193, 1213, 1223, 1237, 1249, 1279, 1291, 1301, 1367, 1811, 1871, 1931, 1979, 2647, 2663

Offset

1,1

Comments

Primes p such that A013636(p) is in A095179.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(3) = 37 is a term because 37 is prime, the next prime is 41, 37*41 = 1517 and its digit reversal 7151 is prime.

Maple

revdigs:= proc(n) local L, i;
  L:= convert(n, base, 10);
  add(L[-i]*10^(i-1), i=1..nops(L))
end proc:
P:= [seq(ithprime(i), i=1..1000)]:
P[select(i -> isprime(revdigs(P[i]*P[i+1])), [$1..999])];

Mathematica

a354881[n_] := Select[Map[Prime, Range[n]], PrimeQ[FromDigits[Reverse[IntegerDigits[# NextPrime[#]]]]]&]
a354881[390] (* Hartmut F. W. Hoft, Jul 20 2022 *)
Select[Partition[Prime[Range[400]], 2, 1], PrimeQ[IntegerReverse[Times@@#]]&][[;; , 1]] (* Harvey P. Dale, Feb 10 2024 *)

Crossrefs

Cf. A013636, A004086, A095179.

Sequence in context: A352347 A172030 A042837 * A162173 A027761 A166306

Adjacent sequences: A354878 A354879 A354880 * A354882 A354883 A354884

Keyword

nonn,base

Author

J. M. Bergot and Robert Israel, Jul 13 2022

Status

approved