A137807 Final digit of prime(n)^2.

4, 9, 5, 9, 1, 9, 9, 1, 9, 1, 1, 9, 1, 9, 9, 9, 1, 1, 9, 1, 9, 1, 9, 1, 9, 1, 9, 9, 1, 9, 9, 1, 9, 1, 1, 1, 9, 9, 9, 9, 1, 1, 1, 9, 9, 1, 1, 9, 9, 1, 9, 1, 1, 1, 9, 9, 1, 1, 9, 1, 9, 9, 9, 1, 9, 9, 1, 9, 9, 1, 9, 1, 9, 9, 1, 9, 1, 9, 1, 1, 1, 1, 1, 9, 1, 9, 1, 9, 1, 9, 9, 1, 9, 1, 1, 9, 1, 1, 9, 1, 9, 9, 9, 1, 1

Offset

1,1

Comments

Euler and Sadek ask whether the sequence, interpreted as the decimal expansion N = 0.49591..., is rational or irrational. - Charles R Greathouse IV, Apr 19 2010

References

R. Euler and J. Sadek, A number that gives the unit digit of n^n. Journal of Recreational Mathematics, 29:3 (1998), pp. 203-204. [From Charles R Greathouse IV, Apr 19 2010]

Links

Table of n, a(n) for n=1..105.

Formula

a(n) = A010879(A001248(n)). - R. J. Mathar, May 03 2008

Maple

A001248 := proc(n) ithprime(n)^2 ; end: A010879 := proc(n) n mod 10 ; end: A137807 := proc(n) A010879(A001248(n)) ; end: seq(A137807(n), n=1..140) ; # R. J. Mathar, May 03 2008

Mathematica

Mod[Prime[Range[110]]^2, 10] (* Harvey P. Dale, Jan 20 2022 *)

Crossrefs

Sequence in context: A242610 A292484 A197418 * A163103 A019688 A365725

Adjacent sequences: A137804 A137805 A137806 * A137808 A137809 A137810

Keyword

nonn,base

Author

Paul Curtz, Apr 29 2008

Extensions

More terms from R. J. Mathar, May 03 2008

Status

approved