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%I #7 May 22 2013 20:34:06
%S 531,5052,24553,107833,999759,2447517,5494392,21711067,68562129,
%T 287617189,437995549,946912755,3567919999,6370211253,10880553708,
%U 17891119105,28464383127,35505127221,97650322329,199757104357,278459342139,517897029319,692671751805
%N Number of conjugacy classes in simply connected Chevalley group E_7(q) as q runs through the prime powers.
%H Eric M. Schmidt, <a href="/A225936/b225936.txt">Table of n, a(n) for n = 1..1000</a>
%H Frank Luebeck, <a href="http://www.math.rwth-aachen.de/~Frank.Luebeck/chev/nrclasses/nrclasses.html">Numbers of Conjugacy Classes in Finite Groups of Lie Type</a>.
%F Let q be the n-th prime power. Then, a(n) is
%F q^7 + q^6 + 2q^5 + 4q^4 + 10q^3 + 15q^2 + 25q + 21 if q == 0 (mod 2);
%F q^7 + q^6 + 2q^5 + 7q^4 + 17q^3 + 35q^2 + 70q + 99 if q == 0 (mod 3);
%F q^7 + q^6 + 2q^5 + 7q^4 + 17q^3 + 35q^2 + 71q + 103 otherwise.
%o (Sage) def A225936(q) : return q^7 + q^6 + 2*q^5 + (4*q^4 + 10*q^3 + 15*q^2 + 25*q + 21 if q%2==0 else 7*q^4 + 17*q^3 + 35*q^2 + 70*q + 99 if q%3==0 else 7*q^4 + 17*q^3 + 35*q^2 + 71*q + 103)
%Y Cf. A188161, A224790, A225928 - A225938.
%K nonn
%O 1,1
%A _Eric M. Schmidt_, May 21 2013
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