A077073 a(1) = 2, a(n+1) is smallest prime factor of (2 * Product_{k=1..n} a(k)) + 1.

2, 5, 3, 61, 7, 25621, 656410021, 8874301, 9137, 1069, 491, 23, 1031, 17, 19, 41, 197, 311, 1187, 113, 11, 1249, 650176342761734684441179196492094381946145205110026217821, 13, 43, 89, 239, 56359, 31732153, 29, 37, 9109, 907, 6323, 293, 811, 77806657

Offset

1,1

Comments

Variation of the Euclid-Mullin sequence A000945.

Links

Table of n, a(n) for n=1..37.

Example

a(5) is equal to 7 because 2*(2*5*3*61)+1 = 3661 = 7 * 523.

Crossrefs

Cf. A000945.

Sequence in context: A308949 A109734 A239309 * A307126 A191474 A199602

Adjacent sequences: A077070 A077071 A077072 * A077074 A077075 A077076

Keyword

nonn

Author

Jason Earls, Nov 29 2002

Extensions

a(26)-a(37) from Robert Price, Jul 20 2015

Status

approved