A242835 Primes formed by the initial digits of the decimal expansion of the square root of 5.

2, 223, 22360679774997896964091

Offset

1,1

Comments

There is no other term with less than 111 digits.

a(4) has 1506 digits. - Hiroaki Yamanouchi, Sep 11 2014

Links

Table of n, a(n) for n=1..3.

Example

Decimal expansion of sqrt(5) begins: 2.23606797749978969640917366... - Wesley Ivan Hurt, May 26 2014

Mathematica

Module[{d=25, f}, f=RealDigits[Sqrt[5], 10, d][[1]]; Select[ Table[ FromDigits[ Take[f, n]], {n, d}], PrimeQ]] (* Harvey P. Dale, Oct 29 2020 *)

Crossrefs

Cf. A005042, A007512, A072952, A119343.

Cf. A002163 (Decimal Expansion of sqrt(5)).

Sequence in context: A117076 A132936 A110715 * A270713 A071225 A212082

Adjacent sequences: A242832 A242833 A242834 * A242836 A242837 A242838

Keyword

nonn,base,bref

Author

Felix Fröhlich, May 23 2014

Status

approved