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A062970
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a(n) = 1 + Sum_{j=1..n} j^j.
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16
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1, 2, 6, 33, 289, 3414, 50070, 873613, 17650829, 405071318, 10405071318, 295716741929, 9211817190185, 312086923782438, 11424093749340454, 449317984130199829, 18896062057839751445, 846136323944176515622, 40192544399240714091046, 2018612200059554303215025
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OFFSET
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0,2
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COMMENTS
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The usual convention in the OEIS is that 0^0 = 1. This sequence could therefore be defined as Sum_{j=0..n} j^j. See also A001923.
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LINKS
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FORMULA
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EXAMPLE
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a(4) = 1 + 1^1 + 2^2 + 3^3 + 4^4 = 1 + 1 + 4 + 27 + 256 = 289.
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MATHEMATICA
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Table[Sum[Sum[Binomial[n, k] StirlingS2[n, k] k!, {k, 0, n}], {n, 0, m}], {m, 0, 20}] (* Geoffrey Critzer, Mar 18 2009 *)
Join[{1}, Accumulate[Table[n^n, {n, 20}]]+1] (* Harvey P. Dale, Aug 31 2016 *)
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PROG
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(PARI) { a=0; for (n=0, 100, write("b062970.txt", n, " ", a+=n^n) ) } \\ Harry J. Smith, Aug 14 2009
(Python)
from itertools import count, accumulate, islice
def A062970_gen(): # generator of terms
yield from accumulate((k**k for k in count(1)), initial=1)
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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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