Search: id:A011966 Results 1-1 of 1 results found. %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). Search completed in 0.001 seconds