[seqfan] Re: nice base-dependent sequence

Robert Gerbicz robert.gerbicz at gmail.com
Tue Jun 1 13:30:20 CEST 2010


I've computed all terms less than 2*10^12, so for the next term a(103)>2e12.
I've used a sieve method to generate the sequence much faster than brute
force: find n in the form n=100*x+y, where 0<=y<100 so at once we examine
100 numbers, let x is given, if you fix a string in n and you want to
determine the y values for that d|100*x+y, then these y values are in (some)
arithmetic progressions.

1 1
2 2
3 6
4 12
5 45
6 54
7 56
8 56
9 245
10 504
11 1440
12 1440
13 5044
14 5044
15 10456
16 10569
17 11704
18 11704
19 11704
20 13608
21 13608
22 13608
23 26460
24 26460
25 198007
26 258064
27 264600
28 264600
29 475440
30 475440
31 1754608
32 1754608
33 2258064
34 2258064
35 2646004
36 2646004
37 2992520
38 11525580
39 12586089
40 12592840
41 12592840
42 12592840
43 18232560
44 18232560
45 18232560
46 18232560
47 117590440
48 117590440
49 117882560
50 134316008
51 138756006
52 192454002
53 349296600
54 349296600
55 349296600
56 349296600
57 349296600
58 1153946800
59 1186966004
60 1186966004
61 1643540850
62 1869660025
63 2488236800
64 2488236800
65 2488236800
66 2488236800
67 11150468640
68 11150468640
69 11150468640
70 11150468640
71 11150468640
72 11150468640
73 15041406912
74 15041406912
75 15041406912
76 15041406912
77 18673200276
78 18673200276
79 63450374408
80 63450374408
81 123657720064
82 124744648800
83 124744648800
84 135074278084
85 138586748800
86 138586748800
87 157350481606
88 157350481606
89 173326400282
90 173326400282
91 462582950404
92 582855080832
93 779187488400
94 779187488400
95 1122243680850
96 1122243680850
97 1396552006664
98 1396552006664
99 1396552006664
100 1396552006664
101 1938976885600
102 1938976885600



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