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Primes p such that the sum of digits of 11*p is 11.
1

%I #11 Oct 24 2022 08:11:44

%S 19,37,73,919,937,991,1873,2791,3637,3673,3691,4591,6373,8191,91837,

%T 91873,92737,92791,93637,94573,181837,181873,181891,182773,183637,

%U 183691,185491,186391,187273,272737,274591,275491,276373,277273,278191,363691,365473,367273,455473,455491,458191,459091

%N Primes p such that the sum of digits of 11*p is 11.

%C Primes in A279771.

%C All terms == 1 (mod 18).

%C Includes (8*10^k+3)/11 for k = 2, 6, 60, 320, 600. Any others?

%H Robert Israel, <a href="/A357935/b357935.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3) = 73 is a term because 73 is prime and 11*73 = 803 with 8+0+3 = 11.

%p filter:= proc(p) convert(convert(11*p,base,10),`+`) = 11 and isprime(p):

%p select(filter, [seq(i,i=1..10^6,18)]);

%t Select[Prime[Range[40000]], Plus @@ IntegerDigits[11*#] == 11 &] (* _Amiram Eldar_, Oct 21 2022 *)

%Y Cf. A166311, A279771.

%K nonn,base

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Oct 21 2022