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 A165459 Primes p such that the sum of the digits of p^2 is 16. 5

%I

%S 13,23,31,41,59,103,131,139,211,229,239,347,401,491,499,571,751,1021,

%T 1201,1229,1453,1489,1499,1741,2003,2011,3001,3821,4001,4639,4649,

%U 5701,7079,8951,10111,10247,10301,10499,14251,14639,16249,17321,19751,20011

%N Primes p such that the sum of the digits of p^2 is 16.

%H Vincenzo Librandi, <a href="/A165459/b165459.txt">Table of n, a(n) for n = 1..80</a>

%F {A000040(i) : A123157(i) = 16}. [_R. J. Mathar_, Nov 09 2009]

%e 31 is in the sequence because 31^2=961 and 9+6+1=16;

%e 1489 is in the sequence because 1489^2=2217121 and 2+2+1+7+1+2+1=16;

%e 3001 is in the sequence because 3001^2=9006001 and 9+0+0+6+0+0+1=16.

%p A007953 := proc(n) local d ; add(d, d=convert(n,base,10)) ; end proc: A165459 := proc(n) local a ; if n = 1 then 13; else a := nextprime( procname(n-1)) ; while A007953(a^2) <> 16 do a := nextprime(a) ; end do ; return a ; end if; end proc: seq(A165459(n),n=1..50) ; # _R. J. Mathar_, Nov 09 2009

%t Select[Prime[Range[3000]], Total[IntegerDigits[#^2]]==16 &] (* _Vincenzo Librandi_, Jun 24 2013 *)

%o (MAGMA) [p: p in PrimesUpTo(3*10^4) | &+Intseq(p^2) eq 16]; // _Bruno Berselli_, Jun 24 2013

%K nonn,less,base

%O 1,1

%A _Vincenzo Librandi_, Sep 20 2009

%E Edited by _N. J. A. Sloane_, Sep 25 2009

%E 347 inserted, more terms added by _R. J. Mathar_, Nov 09 2009

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Last modified June 13 18:45 EDT 2021. Contains 345008 sequences. (Running on oeis4.)