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A263094 Squares in A236562; numbers n^2 such that there is at least one such k for which k - d(k) = n^2, where d(k) is the number of divisors of k (A000005).

%I A263094 #12 Oct 24 2015 12:31:37
%S A263094 0,1,4,9,16,81,121,144,169,225,289,361,441,529,576,625,841,900,961,
%T A263094 1024,1089,1296,1444,1521,1600,1681,1764,1849,1936,2025,2304,2401,
%U A263094 2601,2704,2809,3025,3249,3721,3969,4096,4225,4356,4624,4761,4900,5041,5184,5476,5625,5776,5929,6241,6400,6561,6889,7056,7396,7569,7744,8281,8464,8649,9216,9409,9801,10201,10404,11025
%N A263094 Squares in A236562; numbers n^2 such that there is at least one such k for which k - d(k) = n^2, where d(k) is the number of divisors of k (A000005).
%C A263094 Starting offset is zero, because a(0)=0 is a special case in this sequence.
%H A263094 Antti Karttunen, <a href="/A263094/b263094.txt">Table of n, a(n) for n = 0..20763</a>
%F A263094 a(n) = A000290(A263092(n)).
%t A263094 Take[Select[Sort@ DeleteDuplicates@ Table[n - DivisorSigma[0, n], {n, 20000}], IntegerQ@ Sqrt@ # &], 68] (* _Michael De Vlieger_, Oct 13 2015 *)
%o A263094 (PARI) \\ See code in A263092.
%o A263094 (Scheme) (define (A263094 n) (A000290 (A263092 n)))
%Y A263094 Cf. A000005, A049820, A060990.
%Y A263094 Intersection of A000290 and A236562.
%Y A263094 Cf. A263092 (gives the square roots of these terms).
%Y A263094 Cf. A263095 (complement among squares).
%Y A263094 Cf. A262514 (a subsequence).
%Y A263094 Cf. also A263090, A263098.
%K A263094 nonn
%O A263094 0,3
%A A263094 _Antti Karttunen_, Oct 11 2015