A065991 Numbers k such that the first k base-4 digits of Pi expressed in decimal forms a prime.

1, 62, 3253, 4490, 62622

Offset

1,2

Comments

a(6) > 10^5. - Michael S. Branicky, Aug 14 2025

Links

Table of n, a(n) for n=1..5.

Index entries for sequences related to the number Pi.

Example

The first 62 quaternary digits of Pi (A004603) are 30210033312222020201122030020310301030121202202320003130013031 = 16703571626015105435307505830654230989 in decimal, which is a prime.

Mathematica

Do[ If[ PrimeQ[ FromDigits[ First[ RealDigits[Pi, 4, n]], 4]], Print[n]], {n, 1, 4000} ]

Crossrefs

Cf. A004603, A060421.

Sequence in context: A092709 A308436 A137219 * A206833 A206841 A206895

Adjacent sequences: A065988 A065989 A065990 * A065992 A065993 A065994

Keyword

base,nonn,more

Author

Robert G. Wilson v, Dec 10 2001

Extensions

a(4) from Pontus von Brömssen, Aug 02 2025

a(5) from Michael S. Branicky, Aug 13 2025

Status

approved