A100756 Greatest prime factor of the concatenation of terms in the n-th row of Pascal's Triangle.

11, 11, 11, 11, 2157293, 37562827, 5935701799, 18285670562881, 34298587945253, 92768668286052709, 101410593913295112092414101, 464557485113006356820471, 170574866715037030033, 829618322366629399154147, 2972851397279413777

Offset

1,1

Links

Table of n, a(n) for n=1..15.

Dario Alejandro Alpern, Factorization using the Elliptic Curve Method.

Example

a(4) = 11 is the least prime factor of 14641 = 11^4.
a(5) = 2157293 as 15101051 = 7 * 2157293.

Mathematica

f[n_] := (Table[ #[[1]], {1}] & /@ FactorInteger[ FromDigits[ Flatten[ Table[ IntegerDigits[ Binomial[n, k]], {k, 0, n}]]], FactorComplete -> True])[[ -1, 1]]; Table[ f[n], {n, 10}] (* Robert G. Wilson v, Dec 11 2004 *)

Crossrefs

Cf. A100755.

Sequence in context: A286863 A288121 A278665 * A214757 A278820 A274475

Adjacent sequences: A100753 A100754 A100755 * A100757 A100758 A100759

Keyword

base,easy,nonn

Author

Amarnath Murthy, Nov 23 2004

Extensions

More terms from Robert G. Wilson v, Dec 11 2004

Status

approved