

A100757


Smallest prime factor of the concatenation of terms of the nth row of the Stirling's number of the second kind.


1



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.


CROSSREFS

Cf. A100755, A100756, A100758, A008277.
Sequence in context: A157718 A256957 A046210 * A099677 A142187 A201484
Adjacent sequences: A100754 A100755 A100756 * A100758 A100759 A100760


KEYWORD

base,easy,nonn


AUTHOR

Amarnath Murthy, Nov 23 2004


EXTENSIONS

More terms from R. J. Mathar, Aug 07 2007
More terms from David Wasserman, Mar 06 2008


STATUS

approved



