A089767 - OEIS

%I #14 Dec 10 2017 05:02:17

%S 1,4,25,49,64,81,225,400,676,784,900,1089,1225,1369,1600,1681,2209,

%T 2304,3249,3364,4096,5041,6889,7225,7396,8100,8281,8649,9801,10816,

%U 11025,11236,12100,12544,12769,13924,15876,16384,17424,19881,21609,21904

%N Squares which when concatenated with a 1 gives prime.

%C Squares n such that 10*n+1 is prime. - _Robert Israel_, Dec 09 2017

%H Robert Israel, <a href="/A089767/b089767.txt">Table of n, a(n) for n = 1..10000</a>

%e 41, 4001, 6761 etc. are primes.

%p select(t -> isprime(10*t+1), map(`^`,[$1..300],2)); # _Robert Israel_, Dec 09 2017

%t Select[Range[150]^2, PrimeQ[10 # + 1] &] (* _Michael De Vlieger_, Dec 09 2017 *)

%o (MATLAB) A = []; count = 0; i = 1; while count < 60; s = i*i; if isprime(10*s + 1) A = [A s]; count = count + 1; end; i = i + 1; end; A

%Y Intersection of A000290 and A024912.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Nov 23 2003

%E Corrected and extended by _David Wasserman_, Feb 25 2004