A245075 Difference between least prime factor of n and the digital root of n.

0, 0, -2, 0, -4, 0, -6, -6, 1, 9, -1, 9, -3, -3, -5, 9, -7, 18, 0, 0, -2, 18, -4, -2, -6, -6, 1, 27, -1, 27, -3, -3, -5, -3, -7, 36, 0, 0, -2, 36, -4, 36, -6, -6, 1, 45, -1, 3, -3, -3, -5, 45, -7, 4, 0, 0, -2, 54, -4, 54, -6, -6, 1, 3, -1, 63, -3, -3, -5, 63

Offset

2,3

Links

Jens Kruse Andersen, Table of n, a(n) for n = 2..10000

Example

n    least prime    root(n)    difference
2        2             2            0
3        3             3            0
4        2             4           -2
5        5             5            0
6        2             6           -4
7        7             7            0
8        2             8           -6
9        3             9           -6
10       2             1            1

Prog

(PARI) a(n)=factor(n)[1, 1]-(n-1)%9-1
vector(100, n, a(n+1)) \\ Jens Kruse Andersen, Aug 23 2014

Crossrefs

Cf. A020639, A010888.

Sequence in context: A091371 A144775 A249744 * A046666 A276093 A176296

Adjacent sequences: A245072 A245073 A245074 * A245076 A245077 A245078

Keyword

easy,sign,base

Author

Odimar Fabeny, Aug 21 2014

Extensions

Multiple corrections by Jens Kruse Andersen, Aug 23 2014

Status

approved