%I A001923 M3968 N1639
%S A001923 0,1,5,32,288,3413,50069,873612,17650828,405071317,10405071317,
%T A001923 295716741928,9211817190184,312086923782437,11424093749340453,
%U A001923 449317984130199828,18896062057839751444,846136323944176515621
%N A001923 Sum k^k, k=1..n.
%C A001923 a(n) = A062970(n) - 1.
%C A001923 Starting from the second term, 1, the terms could be described as the 
               special case (n=1; j=1) of the following general formula: a(n) = 
               <from k=j to k=i> Sum [(n + k - 1)]^(k) n=1; j=1; i=1,2,3,...,... 
               For (n=0; j=1) the formula yields A062815 n=0; j=1; i=2,3,4,... For 
               (n=2; j=0) we get A060946 and for (n=3; j=0) A117887. - Alexander 
               Povolotsky (pevnev(AT)juno.com), Sep 01 2007
%D A001923 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A001923 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001923 Azarian, Mohammad K., On the hyperfactorial function, hypertriangular 
               function and the discriminants of certain polynomials. Int. J. Pure 
               Appl. Math. 36 (2007), 251-257.
%D A001923 D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 308.
%D A001923 Problem 4155, Amer. Math. Monthly, 53 (1946), 471.
%H A001923 T. D. Noe, <a href="b001923.txt">Table of n, a(n) for n=0..100</a>
%F A001923 a(n+1)/a(n) > e*n and a(n+1)/a(n) is asymptotic to e*n - Benoit Cloitre 
               (benoit7848c(AT)orange.fr), Sep 29 2002
%t A001923 lst={};s=0;Do[AppendTo[lst, s+=n^n], {n, 4!}];lst [From Vladimir Orlovsky 
               (4vladimir(AT)gmail.com), Sep 27 2008]
%o A001923 (PARI) for(a=1,20,print((sum(x=1,a,x^x)))) - Jorge Coveiro (jorgecoveiro(AT)yahoo.com), 
               Dec 24 2004
%Y A001923 Cf. A073825, A062970 (another version).
%Y A001923 Cf. A062815, A060946, A117887.
%Y A001923 Sequence in context: A102231 A127089 A068102 this_sequence A023880 A104031 
               A023882
%Y A001923 Adjacent sequences: A001920 A001921 A001922 this_sequence A001924 A001925 
               A001926
%K A001923 nonn,easy,nice
%O A001923 0,3
%A A001923 N. J. A. Sloane (njas(AT)research.att.com).