A065989 Numbers k such that the first k ternary digits of Pi expressed in decimal forms a prime.

2, 10, 14, 83, 669, 720, 921, 2944, 4567

Offset: 1

Author

Robert G. Wilson v, Dec 10 2001

Keywords

• base
• nonn
• more

Comments

No further terms up to 10000. - Harvey P. Dale, Oct 14 2018

Examples

			The first 10 ternary digits of Pi (A004602) are 1001021101 = 20611 in decimal, which is a prime.
		

Crossrefs

Cf. A004602.

Programs

Mathematica

Do[ If[ PrimeQ[ FromDigits[ First[ RealDigits[Pi, 2, n]], 2]], Print[n]], {n, 1, 5000} ]
Module[{nn=4600,pd},pd=RealDigits[Pi,3,nn][[1]];Position[Table[ FromDigits[ Take[ pd,n],3],{n,nn}],?(PrimeQ[#]&)]]//Flatten (* _Harvey P. Dale, Oct 14 2018 *)