A328550 a(n) is the least prime p such that the next prime after p with the same last digit as p is p+10*n.

3, 11, 29, 313, 113, 397, 331, 269, 997, 1129, 2861, 4271, 4657, 13451, 10687, 31489, 14969, 10891, 38011, 63113, 39397, 70621, 55373, 57331, 46273, 141863, 78283, 130987, 99233, 27283, 379081, 711371, 349471, 474583, 701033, 155893, 285997, 250307, 988937, 869551, 1118441, 425417, 2385157

Offset

1,1

Comments

Below 4.2*10^13, the largest gap appears at a(339)=19489355556997.

Links

Martin Raab, Table of n, a(n) for n = 1..265 (terms 1..100 from Robert Israel).

Example

a(3) = 29 because the next prime after 29 ending in 9 is 29+3*10=59.

Maple

V:= Vector(50): count:= 0:
L:= Vector(9):
p:= 2:
while count < 50 do
  p:= nextprime(p);
  d:= p mod 10;
  if L[d] = 0 then L[d]:= p
  else
    m:= (p - L[d])/10;
    if m <= 100 and V[m] = 0 then
      V[m]:= L[d]; count:= count+1;
    fi;
    L[d]:= p;
  fi
od:
convert(V, list);

Crossrefs

Sequence in context: A259594 A293010 A236467 * A179234 A338051 A009183

Adjacent sequences: A328547 A328548 A328549 * A328551 A328552 A328553

Keyword

nonn,base

Author

J. M. Bergot and Robert Israel, Jan 19 2021

Status

approved