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A216474
Smallest k such that k*!n +1 is an n-th power.
0
3, 13, 455, 71, 93565703, 40765959421975394881, 27507928745358015883503, 4005456298012605183835102420301535996, 64381553566633030980078485248402475462864768, 67848687916710307026239471566668726955520894650602664910832487
OFFSET
2,1
COMMENTS
!n is a subfactorial number (A000166).
EXAMPLE
a(4) = 455 because 455*!4 + 1 = 455*9+1 = 4096 = 4^6.
MATHEMATICA
a={}; Do[k = 2; While[ !IntegerQ[(k^n - 1)/Subfactorial[n]], k++ ]; AppendTo[a, (k^n-1)/Subfactorial[n]], {n, 2, 11}]; a
CROSSREFS
Cf. A000166.
Sequence in context: A156358 A066266 A092845 * A222762 A290376 A089711
KEYWORD
nonn
AUTHOR
Michel Lagneau, Sep 10 2012
STATUS
approved