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A121945
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a(n) is the sum of the first n factorials in decreasing powers from n to 1. a(n) = Sum_{k = 1..n} k!^(n-k+1).
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1
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1, 3, 11, 69, 929, 30273, 2591057, 614059329, 423463272449, 907403624202753, 6082394749206781697, 140440480114401911810049, 10845109029138237198786147329, 3088811811740393517911301490890753, 3220352134317904958924570965080200574977, 12657255883388612328426763834234183884771442689
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OFFSET
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1,2
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LINKS
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MAPLE
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seq(add(factorial(j)^(n-j+1), j=1..n), n=1..20); # G. C. Greubel, Oct 07 2019
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MATHEMATICA
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Table[Sum[Factorial[i]^(n-i+1), {i, n}], {n, 20}]
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PROG
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(PARI) vector(20, n, sum(j=1, n, (j!)^(n-j+1)) ) \\ G. C. Greubel, Oct 07 2019
(Magma) [(&+[Factorial(j)^(n-j+1): j in [1..n]]): n in [1..20]]; // G. C. Greubel, Oct 07 2019
(Sage) [sum(factorial(j)^(n-j+1) for j in (1..n)) for n in (1..20)] # G. C. Greubel, Oct 07 2019
(GAP) List([1..20], n-> Sum([1..n], j-> Factorial(j)^(n-j+1)) ); # G. C. Greubel, Oct 07 2019
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CROSSREFS
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Similar to A003101 = Sum_{k = 1..n} (n-k+1)^k - only with inserted factorials.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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