login
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).
3
0, 1, 4, 9, 16, 81, 121, 144, 169, 225, 289, 361, 441, 529, 576, 625, 841, 900, 961, 1024, 1089, 1296, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025, 2304, 2401, 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
OFFSET
0,3
COMMENTS
Starting offset is zero, because a(0)=0 is a special case in this sequence.
LINKS
FORMULA
a(n) = A000290(A263092(n)).
MATHEMATICA
Take[Select[Sort@ DeleteDuplicates@ Table[n - DivisorSigma[0, n], {n, 20000}], IntegerQ@ Sqrt@ # &], 68] (* Michael De Vlieger, Oct 13 2015 *)
PROG
(PARI) \\ See code in A263092.
(Scheme) (define (A263094 n) (A000290 (A263092 n)))
CROSSREFS
Intersection of A000290 and A236562.
Cf. A263092 (gives the square roots of these terms).
Cf. A263095 (complement among squares).
Cf. A262514 (a subsequence).
Cf. also A263090, A263098.
Sequence in context: A038784 A038239 A352919 * A226354 A299921 A089149
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 11 2015
STATUS
approved