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Squares of primes, with property that all even digits occur together and all odd digits occur together.
1

%I #13 Jan 04 2024 01:41:55

%S 4,9,25,49,289,841,2209,2809,4489,6241,6889,22201,22801,24649,66049,

%T 80089,208849,426409,466489,822649,2042041,2468041,2866249,2886601,

%U 4068289,6046681,6086089,6466849,6806881,6848689,8082649,8288641,8462281,8826841,22648081,26020201,26822041,28440889,44262409

%N Squares of primes, with property that all even digits occur together and all odd digits occur together.

%C Since the 10's digit of any odd square is even, all digits except the last must be even. - _Robert Israel_, Jan 04 2024

%H Robert Israel, <a href="/A030481/b030481.txt">Table of n, a(n) for n = 1..3000</a>

%p filter:= proc(n) local L;

%p convert(convert(floor(n/10),base,10),set) mod 2 = {0}

%p end proc:

%p [4, 9, op(select(filter, [seq(ithprime(i)^2, i=3..20000)]))]; # _Robert Israel_, Jan 04 2024

%Y Includes (2*10^(2k) + 2*10^k + 1)^2 for k in A296444.

%K nonn,base

%O 1,1

%A _Patrick De Geest_

%E More terms from _Robert Israel_, Jan 04 2024