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A116441 Numbers k which when sandwiched between two 6's give a multiple of k. 1
1, 2, 3, 6, 11, 13, 14, 21, 22, 26, 33, 39, 42, 66, 77, 78, 91, 137, 146, 219, 274, 411, 438, 822, 9091, 19802, 29703, 59406, 909091, 5882353, 10989011, 12145749, 12987013, 13986014, 14354067, 15037594, 20979021, 21978022, 22556391 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..39.

EXAMPLE

39 belongs to the sequence since 6396 is a multiple of 39 (39*164).

MATHEMATICA

f[k_, d_] := Flatten@Table[Select[Divisors[k*(10^(i + 1) + 1)], IntegerLength[ # ] == i &], {i, d}]; f[6, 8] (* Ray Chandler, May 11 2007 *)

Select[Range[23000000], Divisible[FromDigits[Join[{6}, IntegerDigits[#], {6}]], #]&]  (* Harvey P. Dale, Jan 12 2011 *)

CROSSREFS

Cf. A116436-A116444.

Sequence in context: A004038 A152038 A105614 * A116051 A124593 A125882

Adjacent sequences:  A116438 A116439 A116440 * A116442 A116443 A116444

KEYWORD

base,nonn

AUTHOR

Giovanni Resta, Feb 15 2006

STATUS

approved

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Last modified November 28 13:47 EST 2021. Contains 349413 sequences. (Running on oeis4.)