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

1,2

Links

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

Example

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.

Crossrefs

Cf. A261570, A067063, A075023.

Sequence in context: A194706 A110435 A110774 * A067063 A075023 A363099

Adjacent sequences: A261408 A261409 A261410 * A261412 A261413 A261414

Keyword

nonn

Author

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

Extensions

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

Status

approved