A100757 - OEIS

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A100757

Smallest prime factor of the concatenation of terms of the n-th row of the Stirling's number of the second kind.

11, 131, 3, 7, 101, 9066319, 3, 3, 89, 3, 1721, 13, 8761, 1213, 7, 3, 1056688498936034269, 37, 29, 3, 3, 11, 3, 19457, 7, 19, 11, 307, 3, 521, 7, 11887, 3, 3, 7, 3, 13, 11, 103, 43, 22927346902711843, 3, 17, 13, 31, 3, 3, 7, 3, 133811, 37, 11, 13

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OFFSET

2,1

COMMENTS

Sequences from other important triangles with unity as the first and the last term can be contributed.

A061113(8) is the first member of A061113 that is not squarefree; it is divisible by 3^3. - David Wasserman, Mar 06 2008

LINKS

Table of n, a(n) for n=2..54.

FORMULA

a(n) = A020639[A061113(n)]. - R. J. Mathar, Aug 07 2007

EXAMPLE

a(4) = 3 is the least prime factor of 1761.