%I A152018
%S A152018 9,9,81,18,225,81,441,72,729,225,1089,162,1521,441,2025,288,2601,729,
%T A152018 3249,450,3969,1089,4761,648,5625,1521,6561,882,7569,2025,8649,1152,
%U A152018 9801,2601,11025,1458,12321,3249,13689,1800,15129,3969,16641,2178,18225
%N A152018 Denominator of 1/n^2-1/(3n)^2 or of 8/(9n^2).
%C A152018 The associated terms of the n-th main series of the Hydrogen energy spectrum 
               are A000290(3), A061038(6), A061040(9), A061042(12), A061044(15), 
               A061046(18), A061048(21), A061050(24) etc.
%C A152018 All numbers are multiples of 9.
%Y A152018 Cf. A143025 with a similar principle of construction.
%Y A152018 Sequence in context: A014718 A145971 A165830 this_sequence A112296 A038299 
               A165427
%Y A152018 Adjacent sequences: A152015 A152016 A152017 this_sequence A152019 A152020 
               A152021
%K A152018 nonn
%O A152018 1,1
%A A152018 Paul Curtz (bpcrtz(AT)free.fr), Nov 20 2008
%E A152018 Stratified definition, corrected indices, extended, R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Dec 10 2008