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 A128884 Sum of all matrix elements of n X n Vandermonde matrix of numbers 1,2,...,n, i.e., the matrix A with A[i,j] = i^(j-1), 1 <= i <= n, 1 <= j <= n. 0
 1, 5, 23, 144, 1279, 15035, 219463, 3816512, 76928685, 1762344781, 45207853767, 1283438430208, 39944988007339, 1352308628695895, 49471532968242991, 1944732944768690432, 81748776383970349721, 3659142661552743151353 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS p divides a(p+1) for odd primes p. p^2 divides a(p+1) for prime p = {3, 7, 71, ...}. Determinant of n X n Vandermonde matrix of numbers 1,2,...,n equals Product_{k=1..n-1} k! = A000178(n-1) (Superfactorials). LINKS Eric Weisstein's World of Mathematics, Vandermonde Matrix FORMULA a(n) = Sum_{i=1..n, j=1..n} i^(j-1). a(n) = n + Sum_{i=2..n} (i^n-1)/(i-1). MATHEMATICA Table[ n + Sum[ (i^n-1)/(i-1), {i, 2, n} ], {n, 1, 25} ] CROSSREFS Cf. A060946 = Trace of Vandermonde matrix of numbers 1, 2, ..., n. Cf. A000178 = Superfactorials: product of first n factorials. Sequence in context: A129098 A047049 A020034 * A007836 A233568 A157306 Adjacent sequences:  A128881 A128882 A128883 * A128885 A128886 A128887 KEYWORD nonn AUTHOR Alexander Adamchuk, Apr 18 2007 STATUS approved

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Last modified January 26 06:32 EST 2021. Contains 340434 sequences. (Running on oeis4.)