A261411 a(1)=1; thereafter a(n) = smallest prime factor of A261570(n).

1, 11, 3, 11, 41, 3, 239, 11, 3, 11, 11, 3, 11, 11, 3, 11, 11, 3, 71, 21557, 19, 17, 31, 181, 17, 353, 19, 31, 19, 29, 17, 29, 11616377, 214141, 19, 5471, 17, 13883, 3, 7, 421219193, 3, 17, 7, 3, 7, 101, 3, 634324033999, 13, 19, 13, 83, 13, 23, 13, 19, 13, 19

Offset: 1

Author

N. J. A. Sloane, Aug 24 2015, based on Robert G. Wilson v's comment in A261570

Keywords

• nonn

Examples

			A261570(11) = 12345678911987654321 = (11)(59)(34631)(43117)(6373)(1999), so a(10) = 11.
Note that a(2007) = A261570(2007) is a 21233-digit (probable) prime.
		

Links

• David Broadhurst and Hiroaki Yamanouchi, Table of n, a(n) for n = 1..99 (First 61 terms from Hiroaki Yamanouchi)

Crossrefs

Cf. A261570, A067063, A075023.

Extensions

a(41)-a(59) from Hiroaki Yamanouchi, Aug 24 2015