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A124405
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Sum[ i^j, {i,1,n}, {j,1,n} ] + 1.
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3
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2, 9, 57, 495, 5700, 82201, 1419761, 28501117, 651233662, 16676686697, 472883843993, 14705395791307, 497538872883728, 18193397941038737, 714950006521386977, 30046260016074301945, 1344648068888240941018
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| p divides a(p) and a(p-1) for prime p.
p^2 divides a(p) for prime p in {5, 13, 563, ...} which seems to coincide with the Wilson primes (A007540).
p^2 divides a(p-1) for prime p in {3, 11, 107, ...} which seems to coincide with the odd primes in A079853.
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FORMULA
| a(n) = Sum[ i^j, {i,1,n}, {j,1,n} ] + 1 = Sum[ i*(i^n-1)/(i-1), {i,2,n} ] + n + 1.
a(n) = A086787(n) + 1.
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MATHEMATICA
| Table[Sum[i^j, {i, 1, n}, {j, 1, n}]+1, {n, 1, 20}]
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CROSSREFS
| Cf. A086787, A079853, A007540
Sequence in context: A175912 A111545 A070075 * A141787 A047852 A116867
Adjacent sequences: A124402 A124403 A124404 * A124406 A124407 A124408
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KEYWORD
| nonn
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Dec 14 2006
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EXTENSIONS
| Edited by Max Alekseyev (maxale(AT)gmail.com), Jan 29 2012
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