%I A011966
%S A011966 1,5,20,87,409,2066,11155,64077,389946,2504665,16923381,119928232,
%T A011966 888980293,6876320041,55382419676,463539664643,4024626253845,
%U A011966 36189297168874,336513491259647,3231446022478129,32004743929977258
%N A011966 Third differences of Bell numbers.
%C A011966 Number of partitions of n+4 with at least one singleton and with the 
               smallest element in a singleton equal to 4. Alternatively, number 
               of partitions of n+4 with at least one singleton and with the largest 
               element in a singleton equal to n+1. - Olivier GERARD (olivier.gerard(AT)gmail.com), 
               Oct 29 2007
%D A011966 Olivier Gerard and Karol A. Penson, A budget of set partition statistics, 
               in preparation.
%p A011966 a:= n-> sum ((-1)^(k+1) *binomial(3,k) *combinat['bell'](n+k), k=0..3): 
               seq (a(n), n=0..20); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), 
               Sep 05 2008]
%Y A011966 Cf. A000110.
%Y A011966 Cf. A005493, A011965.
%Y A011966 Sequence in context: A145932 A026661 A099014 this_sequence A017966 A002745 
               A020046
%Y A011966 Adjacent sequences: A011963 A011964 A011965 this_sequence A011967 A011968 
               A011969
%K A011966 nonn
%O A011966 0,2
%A A011966 N. J. A. Sloane (njas(AT)research.att.com).