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A001099
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a(n) = n^n - a(n-1), with a(1) = 1.
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4
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1, 3, 24, 232, 2893, 43763, 779780, 15997436, 371423053, 9628576947, 275683093664, 8640417354592, 294234689237661, 10817772136320355, 427076118244539020, 18019667955465012596, 809220593930871751581, 38537187481365665823843, 1939882468178947923300136
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OFFSET
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1,2
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LINKS
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FORMULA
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Absolute value of Sum_{k=1..n} k^k*(-1)^(k+1). a(n) = n^n - (n-1)^(n-1) + (n-2)^(n-2) - ... - (-1)^n*1^1. - Alexander Adamchuk, Jun 30 2006
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MATHEMATICA
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Abs[Table[Sum[k^k*(-1)^(k+1), {k, 1, n}], {n, 1, 30}]] (* Alexander Adamchuk, Jun 30 2006 *)
RecurrenceTable[{a[1]==1, a[n]==n^n-a[n-1]}, a, {n, 20}] (* Harvey P. Dale, Jan 21 2015 *)
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PROG
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(Python)
from itertools import accumulate, count, islice
def A001099_gen(): # generator of terms
yield from accumulate((k**k for k in count(1)), func=lambda x, y:y-x)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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