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Glaisher's function G(n) (18 squares version).
(Formerly M5088 N2203)
3

%I M5088 N2203 #25 Oct 17 2023 07:17:57

%S 1,-20,-80,144,610,-448,-1120,2240,-3423,-12200,14800,29440,-5470,

%T -6272,-48800,-81664,73090,68460,15600,87840,-139776,82880,189920,

%U -474112,-18525,109400,-251040,412160,-128222,-273280,54400,1059840,1847040

%N Glaisher's function G(n) (18 squares version).

%C It would be nice to have a q-series that generates this sequence. Glaisher gives many formulas but they are difficult to follow.

%D J. W. L. Glaisher, On the representation of a number as sum of 18 squares, Quart. J. Math. 38 (1907), 289-351 (see p. 311). [The whole 1907 volume of The Quarterly Journal of Pure and Applied Mathematics, volume 38, is freely available from Google Books]

%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Sean A. Irvine, <a href="/A002609/b002609.txt">Table of n, a(n) for n = 1..500</a>

%H <a href="/index/Ge#Glaisher">Index entries for sequences mentioned by Glaisher</a>

%F a(n) = A002611(2*n) - 16*A002611(n). - _Sean A. Irvine_, Mar 04 2019

%Y Different from A002111 (another Glaisher G(n)).

%K sign

%O 1,2

%A _N. J. A. Sloane_

%E Edited and signs added by _N. J. A. Sloane_, Nov 26 2018

%E More terms from _Sean A. Irvine_, Mar 04 2019