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 A321581 a(n) is the sum of first n natural numbers raised to the product of first n natural numbers. 0
 0, 1, 9, 46656, 1000000000000000000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS The next term a(5) has 142 decimal digits. LINKS FORMULA a(n) = (n*(n+1)/2)^(n!). a(n) = A000217(n)^A000142(n). EXAMPLE a(3) = (1+2+3)^3! = 6^6 = 46656. MAPLE [(n*(n+1)/2)^factorial(n)\$n=0..5]; # Muniru A Asiru, Dec 20 2018 MATHEMATICA a[n_] := (n*(n + 1)/2)^n!; Array[a, 5] (* Amiram Eldar, Nov 13 2018 *) PROG (PARI) a(n)=(n*(n+1)/2)^(n!); \\ Andrew Howroyd, Nov 13 2018 (GAP) List([1..5], n->(n*(n+1)/2)^(Factorial(n))); # Stefano Spezia, Nov 21 2018 CROSSREFS Cf. A000142, A000217, A067055. Sequence in context: A242853 A198478 A159398 * A053971 A013790 A271103 Adjacent sequences:  A321578 A321579 A321580 * A321582 A321583 A321584 KEYWORD nonn,easy AUTHOR Ayush Kumar Jha, Nov 13 2018 STATUS approved

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Last modified August 11 15:12 EDT 2020. Contains 336428 sequences. (Running on oeis4.)