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A244348 Integers n such that for every integer k>0, n*10^k+1 has a divisor in the set { 11, 73, 101, 137 }. 2
162207, 1622070, 3349554, 5109589, 6651446, 7001622, 9589051, 10958905, 11273318, 12733181, 14460665, 16220700, 17762557, 18112733, 20700162, 22070016, 22384429, 23844292, 25571776, 27331811, 28873668, 29223844, 31811273, 33181127, 33495540, 34955403, 36682887 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
For n > 8, a(n) = a(n-8) + 11111111, the first 8 values are in the data.
If n is of the form 3*m+2, n*10^k+1 is always divisible by 3 but also has a divisor in the set { 11, 73, 101, 137 }.
If k of the form 2*j+1, n*10^(2*j+1)-1 is divisible by 11.
If k of the form 8*j, n*10^(8*j)-1 is divisible by 137.
If k of the form 4*j+2, n*10^(4*j+2))-1 is divisible by 101.
If k of the form 8*j+4 then n*10^(8*j+4)-1 is divisible by 73.
This covers all k, so the covering set is { 11, 73, 101, 137 }.
LINKS
FORMULA
for n > 8, a(n) = a(n-8) + 11111111.
CROSSREFS
Sequence in context: A120409 A253466 A225811 * A083633 A043649 A282948
KEYWORD
nonn,easy
AUTHOR
Pierre CAMI, Jun 28 2014
EXTENSIONS
More terms from Giovanni Resta, Nov 23 2019
STATUS
approved

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Last modified February 22 18:56 EST 2024. Contains 370260 sequences. (Running on oeis4.)