A245075 - OEIS

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A245075

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

1

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

(list; graph; refs; listen; history; text; internal format)

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