A118329 Catalan-primes: primes formed from the concatenation of initial decimal digits of Catalan's constant.

9159655941772190150546035149323841107741493742816721

Offset: 1

Author

Eric W. Weisstein, Apr 25 2006

Keywords

• nonn
• bref
• base

Comments

Next term has 276 digits and so is too large to include.

Examples

			C = 0.915965594177... and the 52-digit number a(1) = 9159655941772190150546035149323841107741493742816721 is prime.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..2
• Tanya Khovanova, Non Recursions.
• Eric Weisstein's World of Mathematics, Constant Primes.
• Eric Weisstein's World of Mathematics, Integer Sequence Primes.
• Index entries for one-term sequences.

Crossrefs

Cf. A006752, A118328.

Programs

Mathematica

Select[Floor[Catalan*10^Range[0, 300]], PrimeQ] (* Amiram Eldar, Jul 09 2025 *)

Formula

a(n) = floor(A006752 * 10^(A118328(n)-1)). - Amiram Eldar, Jul 09 2025

Extensions

Edited by Charles R Greathouse IV, Apr 27 2010