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A262376
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a(n) = Sum_{k=0..n} (k! - k).
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1
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1, 1, 1, 4, 24, 139, 853, 5886, 46198, 409069, 4037859, 43954648, 522956236, 6749977023, 93928268209, 1401602636194, 22324392524178, 378011820620161, 6780385526348143, 128425485935180124, 2561327494111820104, 53652269665821260083, 1177652997443428940061
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listen;
history;
text;
internal format)
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OFFSET
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0,4
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} k! - k.
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EXAMPLE
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a(3) = 4, which is the following sum: (0!-0) + (1!-1) + (2!-2) + (3!-3).
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MATHEMATICA
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PROG
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(Sidef)
var sum = 0;
range(0, 10).each { |n|
sum += (n! - n);
say(n, "\t", sum);
};
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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