A167414 - OEIS

%I #11 May 10 2019 22:14:09

%S 2,127,149,211,251,271,277,347,419,457,491,521,523,541,547,587,727,

%T 743,853,857,941,1021,1049,1061,1087,1201,1223,1229,1249,1289,1373,

%U 1409,1423,1429,1483,1553,1559,1601,1621,1627,1733,1753,1861,1867,1951,1973

%N Primes p such that sum of their squared decimal digits, minus one, is prime.

%C 127 is a term because 1^2 + 2^2 + 7^2 - 1 = 53 (prime);

%C 149 is a term because 1^2 + 4^2 + 9^2 - 1 = 97;

%C 347 is a term because 3^2 + 4^2 + 7^2 - 1 = 73.

%H Vincenzo Librandi, <a href="/A167414/b167414.txt">Table of n, a(n) for n = 1..1300</a>

%p A003132 := proc(n) local d; add(d^2,d=convert(n,base,10)) ; end proc: A167414 := proc(n) local p; if n = 1 then 2; else p := nextprime(procname(n-1)) ; while not isprime(A003132(p)-1) do p := nextprime(p) ; end do ; return p end if ; end proc: seq(A167414(n),n=1..80) ; # _R. J. Mathar_, Nov 04 2009

%t Select[Prime[Range[3000]], PrimeQ[Total[IntegerDigits[#]^2] - 1] &] (* _Vincenzo Librandi_, Sep 25 2014 *)

%Y Cf. A167412.

%K nonn,base

%O 1,1

%A _Vincenzo Librandi_, Nov 03 2009

%E 2 and terms larger than 941 added by _R. J. Mathar_, Nov 04 2009