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A115690 Squares whose digit reversal is a powerful(1) number (A001694).

%I A115690 #15 Nov 01 2022 13:48:40
%S A115690 1,4,9,100,121,144,169,400,441,484,576,676,900,961,1089,9801,10000,
%T A115690 10201,10404,10609,12100,12321,12544,12769,14400,14641,14884,16900,
%U A115690 25281,27225,40000,40401,40804,44100,44521,44944,48400,48841,57600
%N A115690 Squares whose digit reversal is a powerful(1) number (A001694).
%C A115690 If x is a member, then so is 100*x. - _Robert Israel_, Mar 16 2020
%H A115690 Robert Israel, <a href="/A115690/b115690.txt">Table of n, a(n) for n = 1..1500</a>
%F A115690 Trivially, n^2 <= a(n) <= 100^(n-1). - _Charles R Greathouse IV_, Nov 01 2022
%e A115690 25281=159^2 and 18252=2^2*3^3*13^2 is powerful.
%p A115690 filter:= proc(n) local L,i,x;
%p A115690   L:= convert(n,base,10);
%p A115690   x:=add(L[-i]*10^(i-1),i=1..nops(L));
%p A115690   andmap(t -> t[2]>=2, ifactors(x)[2]):
%p A115690 end proc:select(filter, [seq(i^2,i=1..10^4)]); # _Robert Israel_, Mar 16 2020
%o A115690 (PARI) is(k) = ispowerful(fromdigits(Vecrev(digits(k))));
%o A115690 select(is, vector(300, n, n^2)) \\ _Michel Marcus_, Nov 01 2022
%Y A115690 Subsequence of A115656.
%Y A115690 A033294 is a subsequence, and the main entry for this sequence.
%Y A115690 Cf. A001694, A115689.
%K A115690 nonn,base
%O A115690 1,2
%A A115690 _Giovanni Resta_, Jan 31 2006