A048420 Primes whose consecutive digits differ by 8 or 9.

2, 3, 5, 7, 19, 191, 809, 919, 9091, 80809, 80909, 91909, 190909, 909091, 1908091, 1909091, 9090919, 9091909, 19090909, 80919191, 190909091, 191908091, 809080919, 809191919, 908080909, 919080919, 919191919, 1909080809

Offset

1,1

Links

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

Maple

extend:= proc(n) local d, x;
  d:= n mod 10;
  seq(10*n+x, x = select(t -> t >= 0 and t <= 9, [d-9, d-8, d+8, d+9]))
end proc:
R:= 2, 3, 5, 7: count:= 4:
T:= [$1..9]:
for d from 2 while count < 100 do
  T:= map(extend, T);
  V:= select(isprime, T);
  count:= count+nops(V);
  R:= R, op(V);
od:
R; # Robert Israel, Oct 17 2023

Mathematica

Join[{2, 3, 5, 7}, Select[FromDigits/@Tuples[{0, 1, 8, 9}, 10], PrimeQ[#] && AllTrue[ Abs[ Differences[ IntegerDigits[#]]], #>7&]&]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Oct 08 2017 *)

Crossrefs

Cf. A048413-A048419.

Sequence in context: A236303 A117315 A158473 * A048405 A110457 A320584

Adjacent sequences: A048417 A048418 A048419 * A048421 A048422 A048423

Keyword

nonn,base

Author

Patrick De Geest, Apr 15 1999

Extensions

More terms from Naohiro Nomoto, Jul 28 2001

Status

approved