A073637 Digital root (cf. A010888) of prime(n)^3.

8, 9, 8, 1, 8, 1, 8, 1, 8, 8, 1, 1, 8, 1, 8, 8, 8, 1, 1, 8, 1, 1, 8, 8, 1, 8, 1, 8, 1, 8, 1, 8, 8, 1, 8, 1, 1, 1, 8, 8, 8, 1, 8, 1, 8, 1, 1, 1, 8, 1, 8, 8, 1, 8, 8, 8, 8, 1, 1, 8, 1, 8, 1, 8, 1, 8, 1, 1, 8, 1, 8, 8, 1, 1, 1, 8, 8, 1, 8, 1, 8, 1, 8, 1, 1, 8, 8, 1, 8, 1, 8, 8, 1, 8, 1, 8, 8, 8, 1, 1

Offset

1,1

Comments

Apart from a(2)=9 all other terms are either 1 or 8.

Links

Table of n, a(n) for n=1..100.

Example

a(3)=8 because p(3)=5 and 5^3=125 -> sum-of-digits = 8. a(4)=1 because p(3)=7 and 7^3=343 -> sum-of-digits = 10 -> sum-of-digits = 1.

Mathematica

n=3; su[x_] := Sum[IntegerDigits[x][[i]], {i, Length[IntegerDigits[x]]}]; Table[su[su[su[su[Prime[x]^n]]]], {x, 100}]
Table[If[(m9=Mod[Prime[n]^3, 9])==0, 9, m9], {n, 200}]

Crossrefs

Cf. A010888, A021596, A056992, A010888, A038194, A166923.

Sequence in context: A195341 A205185 A011463 * A153202 A019738 A236098

Adjacent sequences: A073634 A073635 A073636 * A073638 A073639 A073640

Keyword

nonn,base

Author

Zak Seidov, Sep 01 2002, Oct 23 2009

Extensions

Edited by N. J. A. Sloane, Oct 29 2009

Status

approved