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%I #15 Sep 08 2022 08:45:47
%S 17,37,53,73,89,107,109,127,181,199,269,271,379,503,521,557,701,739,
%T 1009,1061,1097,1151,1171,1439,1511,1601,1619,1747,1801,1871,2251,
%U 3169,3259,3329,3347,3511,3761,3851,3889,4051,4139,4519,4751,4951,5003,5021,5849
%N Primes p where the digital sum of p^2 is equal to 19.
%H Vincenzo Librandi, <a href="/A165493/b165493.txt">Table of n, a(n) for n = 1..215</a>
%F {A000040(i) : A123157(i) = 19} [_R. J. Mathar_, Sep 29 2009]
%e 17 is in the sequence because 17^2=289 and 2+8+9=19.
%e 1801 is in the sequence because 1801^2=3243601 and 3+2+4+3+6+0+1=19.
%p A007953 := proc(n) add(d,d=convert(n,base,10)) ; end:
%p A123157 := proc(n) A007953((ithprime(n))^2) ; end:
%p for n from 1 to 100000 do if A123157(n) = 19 then printf("%d,",ithprime(n)) ; fi; od: # _R. J. Mathar_, Sep 29 2009
%t Select[Prime[Range[800]], Total[IntegerDigits[#^2]]== 19&] (* _Vincenzo Librandi_, Jun 24 2013 *)
%o (Magma) [p: p in PrimesUpTo(6000) | &+Intseq(p^2) eq 19]; // _Bruno Berselli_, Jun 24 2013
%K nonn,base
%O 1,1
%A _Vincenzo Librandi_, Sep 21 2009
%E More terms from _R. J. Mathar_, Sep 29 2009