

A242835


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


0




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 FrÃ¶hlich, May 23 2014


STATUS

approved



