Search: id:A060946
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%I A060946
%S A060946 1,3,12,76,701,8477,126126,2223278,45269999,1045269999,
%T A060946 26982694600,769991065288,24068076187769,817782849441913,30010708874832538
%N A060946 Trace of Vandermonde matrix of numbers 1,2,..n, i.e. the matrix A with 
               A[i,j] = i^j, 1 <= i <= n, 0 <= j <= n-1.
%C A060946 A member of the family of sequences defined by a(n) = sum_{i=1..n}[i*c(1)*..*c(r)]^(i-1); 
               c(i) integers. Here c(1)=1. - Ctibor O. ZIZKA (ctibor.zizka(AT)seznam.cz), 
               Feb 23 2008
%H A060946 Harry J. Smith, <a href="b060946.txt">Table of n, a(n) for n=1,...,100</
               a>
%H A060946 C. P. Simoes, <a href="http://www.cpsimoes.net/tdm/tdm.html">Teste de 
               Desempenho Mental</a>.
%F A060946 a(n) = sum k=1, ..n k^(k-1)
%e A060946 a(3) = 12 because the matrix is: 1,1,1 1,2,4 1,3,9 and the trace is 1+2+9 
               = 12
%e A060946 1 = 1^0; 3 = 1^0 + 2^1; 12 = 1^0 + 2^1 + 3^2; 76 = 1^0 + 2^1 + 3^2 + 
               4^3
%p A060946 a:=n->sum ((j+1)^j, j=0..n): seq(a(n), n=0..17);# [From Zerinvary Lajos 
               (zerinvarylajos(AT)yahoo.com), Dec 17 2008]
%t A060946 Table[Sum[i^(i-1), {i, n}], {n, 15}]
%o A060946 (PARI) { for (n=1, 100, write("b060946.txt", n, " ", sum(k=1, n, k^(k 
               - 1))); ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 
               15 2009]
%Y A060946 A000178, A001923.
%Y A060946 Cf. A000169.
%Y A060946 Sequence in context: A134524 A120591 A032114 this_sequence A121421 A108043 
               A058561
%Y A060946 Adjacent sequences: A060943 A060944 A060945 this_sequence A060947 A060948 
               A060949
%K A060946 nonn
%O A060946 1,2
%A A060946 Ahmed Fares (ahmedfares(AT)my-deja.com), May 08 2001
%E A060946 More terms from Zak Seidov (zakseidov(AT)yahoo.com), Jul 07 2003

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