A038526 -id:A038526 - cp's OEIS frontend

A038524 Numbers k such that the k-th Fibonacci number is composite and the concatenation of its prime factors (written in base 10 in ascending order) is prime.

8, 24, 28, 34, 50, 52, 58, 71, 77, 163, 197, 235, 238, 319, 570, 669, 949, 958, 1211, 1305

Offset: 1

			F(24) = 46368 = 2^5 * 3^2 * 7 * 23 is composite and the concatenation 2222233723 is prime, so 24 is in the sequence.

Blair Kelly, Fibonacci and Lucas Factorizations.

Cf. A000045, A037276, A038526.

More terms from Jens Kruse Andersen, Jan 05 2003
a(17)-a(18) from Ryan Propper, May 29 2006
a(19)-a(20) from Sean A. Irvine, Jan 16 2021

A038525 Numbers n with property that either the n-th Fibonacci number is prime or the concatenation of its prime factors is prime.

Original entry on oeis.org

3, 4, 5, 7, 8, 11, 13, 17, 23, 24, 28, 29, 34, 43, 47, 50, 52, 58, 71, 77, 83, 131, 137, 163, 197, 235, 238, 319, 359, 431, 433, 449, 509, 569, 570, 571, 669, 949, 958, 1211, 1305

Offset: 1

Jeff Burch

Up to and including a(17)=52, the sequence are the n such that A038526(n) is prime. Extrapolating, one would expect it to continue 83,86,93,95,131,137,139,174,182,... - R. J. Mathar, Oct 12 2007

Cf. A000045, A037276, A038526.

More terms from Thomas Baruchel, Oct 11 2003

More terms from Sean A. Irvine, Jan 16 2021

cp's OEIS Frontend

A038524 Numbers k such that the k-th Fibonacci number is composite and the concatenation of its prime factors (written in base 10 in ascending order) is prime.

Views

Author

Keywords

Examples

Links

Crossrefs

Extensions