A356184 - OEIS

A356184

Triangle read by rows: n-th row gives the indices of the n repunits that divide A340549(n).

1, 1, 2, 1, 2, 4, 1, 2, 3, 6, 1, 2, 3, 4, 6, 1, 2, 3, 4, 6, 12, 1, 2, 3, 4, 6, 8, 12, 1, 2, 3, 4, 5, 6, 10, 12, 1, 2, 3, 4, 5, 6, 8, 10, 12, 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 18, 20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 18, 20, 24

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..98.

EXAMPLE

Triangle begins:

1, 2;

1, 2, 4;

1, 2, 3, 6;

1, 2, 3, 4, 6;

1, 2, 3, 4, 6, 12;

1, 2, 3, 4, 6, 8, 12;

1, 2, 3, 4, 5, 6, 10, 12;

1, 2, 3, 4, 5, 6, 8, 10, 12;

1, 2, 3, 4, 5, 6, 8, 9, 10, 12;

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 18;

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14;

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 18;

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 18;

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 18, 20;

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 18, 20, 24;

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24;

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24, 30;

...

The 5th row is {1, 2, 3, 4, 6} since A340549(5) = 11222211 is the least integer that is divisible by five repunits and these are R_1, R_2, R_3, R_4 and R_6.

CROSSREFS

Cf. A002275, A004023, A083230, A340549.

Sequence in context: A081517 A374577 A104778 * A292477 A081532 A174843

Adjacent sequences: A356181 A356182 A356183 * A356185 A356186 A356187

KEYWORD

nonn,base,tabl

AUTHOR

Bernard Schott, Jul 28 2022

STATUS

approved