|
| |
|
|
A069187
|
|
Numbers k such that core(k) = ceiling(sqrt(k)) where core(k) is the squarefree part of k (the smallest integer such that k*core(k) is a square).
|
|
3
|
|
|
|
1, 2, 20, 90, 272, 650, 1332, 4160, 6642, 10100, 14762, 20880, 28730, 38612, 50850, 65792, 83810, 130682, 160400, 194922, 234740, 280370, 332352, 391250, 457652, 532170, 615440, 708122, 810900, 924482, 1187010, 1337492, 1501850, 1680912, 1875530, 2314962, 2561600
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
Conjecture: sequence is A071253 minus those entries of A071253 that have their index in A049532, i.e., a(n) is of form n^2*(n^2+1) for all n not in A049532. - Ralf Stephan, Aug 18 2004
|
|
|
LINKS
|
Amiram Eldar, Table of n, a(n) for n = 1..300
|
|
|
MATHEMATICA
|
core[n_] := Times @@ Apply[ Power, {#[[1]], Mod[#[[2]], 2]}& /@ FactorInteger[n], {1}]; Select[Range[500000], core[#] == Ceiling[Sqrt[#]]&] (* Jean-François Alcover, Jul 26 2011 *)
|
|
|
CROSSREFS
|
Cf. A007913, A049532, A071253.
Sequence in context: A279264 A063663 A071253 * A328510 A033840 A086755
Adjacent sequences: A069184 A069185 A069186 * A069188 A069189 A069190
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Benoit Cloitre, Apr 14 2002
|
|
|
EXTENSIONS
|
More terms from Amiram Eldar, Sep 10 2020
|
|
|
STATUS
|
approved
|
| |
|
|
