|
|
A328207
|
|
Starts of runs of 4 consecutive factorial base Niven numbers (A118363).
|
|
11
|
|
|
9320542, 11397166, 29048470, 29394574, 40469902, 40816006, 58467310, 72657574, 84079006, 101730310, 178911502, 200716054, 283088806, 479329774, 485213542, 499403806, 528476542, 530553166, 544743430, 559625902, 559972006, 574162270, 603235006, 617425270, 641652550
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Dahlenberg & Edgar proved that this sequence is infinite and that there are no consecutive runs of 5 or more factorial base Niven numbers.
a(1)-a(18) were calculated by Dahlenberg & Edgar.
|
|
LINKS
|
|
|
EXAMPLE
|
9320542 is in the sequence since 9320542, 9320543, 9320544 and 9320545 are all in A118363: A034968(9320542) = 22 is a divisor of 9320542, A034968(9320543) = 23 is a divisor of 9320543, A034968(9320544) = 18 is a divisor of 9320544, and A034968(9320545) = 19 is a divisor of 9320545.
|
|
MATHEMATICA
|
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, 3], fnQ]; Select[Range[10^8], aQ] (* after Jean-François Alcover at A034968 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|