A371390 Numbers k such that prime(k), prime(k+1), prime(k+2), prime(k+3) and prime(k+4) all have the same last digit.

11582, 17385, 19317, 20579, 22931, 42098, 51895, 52252, 55259, 60393, 62192, 62193, 62680, 64050, 65324, 71483, 76391, 76773, 76805, 77052, 81139, 86711, 95661, 100208, 102032, 113646, 113892, 113954, 115251, 124227, 125218, 125586, 144165, 144299, 147619, 147620

Offset

1,1

Links

Table of n, a(n) for n=1..36.

David A. Corneth, PARI program

Example

11582 is a term because prime(11582) = 123229, prime(11583) = 123239, prime(11584) = 123259, prime(11585) = 123269 with the same last digit 9.

Maple

nn:=15*10^4:d:=array(1..5):
for n from 1 to nn do:
 for k from 1 to 5 do:
   d[k]:=irem(ithprime(n+k-1), 10):
 od:
  if d[1]=d[2] and d[1]=d[3] and
d[1]=d[4] and d[1]=d[5]
    then
     printf(`%d, `, n):
    else
  fi:
od:

Prog

(PARI) \\ See PARI link
(Python)
from itertools import count, islice
from sympy import nextprime
def A371390_gen(): # generator of terms
    xlist, p = [2, 3, 5, 7, 1], 11
    for k in count(1):
        if len(set(xlist)) == 1:
            yield k
        p = nextprime(p)
        xlist = xlist[1:]+[p%10]
A371390_list = list(islice(A371390_gen(), 10)) # Chai Wah Wu, Apr 13 2024

Crossrefs

Cf. A000040, A007652, A107730, A129750.

Sequence in context: A063434 A205982 A066055 * A184685 A203387 A218105

Adjacent sequences: A371387 A371388 A371389 * A371391 A371392 A371393

Keyword

nonn,base

Author

Michel Lagneau, Mar 20 2024

Status

approved