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A328205
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Numbers m such that m and m+1 are consecutive factorial base Niven numbers (A118363).
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19
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1, 8, 26, 35, 90, 122, 244, 245, 300, 384, 440, 510, 722, 804, 844, 845, 935, 944, 984, 1014, 1079, 1224, 1232, 1444, 1445, 1518, 1584, 1589, 1727, 1728, 1736, 1770, 1880, 2159, 2184, 2232, 2240, 2528, 2540, 2650, 2820, 2980, 3032, 3263, 3640, 4199, 4328, 4848
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OFFSET
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1,2
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COMMENTS
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Dahlenberg & Edgar proved that this sequence is infinite.
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LINKS
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EXAMPLE
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8 is in the sequence since both 8 and 9 are in A118363. A034968(8) = 2 is a divisor of 8 and A034968(9) = 3 is a divisor of 9.
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MATHEMATICA
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sf[n_] := Module[{s = 0, i = 2, k = n}, While[k > 0, k = Floor[n/i!]; s = s + (i - 1)*k; i++]; n - s]; fnQ[n_] := Divisible[n, sf[n]]; aQ[n_] := AllTrue[n + Range[0, 1], fnQ]; Select[Range[5000], aQ] (* after Jean-François Alcover at A034968 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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