A271043 Primes p such that p and prime(p) end with the same digit.

7, 11, 23, 29, 37, 103, 107, 109, 149, 239, 271, 277, 293, 307, 331, 367, 379, 431, 449, 499, 503, 541, 557, 577, 601, 701, 751, 761, 787, 821, 823, 839, 881, 883, 907, 953, 967, 983, 991, 1031, 1033, 1097, 1163, 1171, 1213, 1223, 1249, 1289, 1321, 1433

Offset

1,1

Comments

Subsequence of A067790.

Matches A067790 for the first eight terms. It appears that after that, most terms of that sequence are composite. For example, a(1000) = 37447, which is A067790(3751), meaning that that other sequence has 2751 composite terms less than 37447. - Alonso del Arte, Jan 23 2020

Links

Colin Barker, Table of n, a(n) for n = 1..1000

Example

29 is in the sequence because 29 mod 10 = 9, prime(29) = 109 and 109 mod 10 = 9 also.
31 is not in the sequence because 31 mod 10 = 1 but prime(31) = 113 and 113 mod 10 = 3, not 1.

Mathematica

Select[Prime@ Range@ 250, Mod[#, 10] == Mod[Prime@ #, 10] &] (* Michael De Vlieger, Mar 29 2016 *)

Prog

(PARI) L=List(); forprime(p=2, 2000, if(p%10==prime(p)%10, listput(L, p))); Vec(L)
(Python)
from sympy import isprime, prime
for p in range(2, 10**4):
    if(prime(p)%10==p%10 and isprime(p)):print(p)
# Soumil Mandal, Apr 06 2016

Crossrefs

Cf. A067790, A271044, A271045, A271046.

Sequence in context: A095084 A182569 A067790 * A089056 A210981 A372303

Adjacent sequences: A271040 A271041 A271042 * A271044 A271045 A271046

Keyword

nonn,easy,base

Author

Colin Barker, Mar 29 2016

Status

approved