A226056 a(n) = Number of common trailing terms on the row n of tables A225632 and A225642.

1, 1, 1, 2, 2, 2, 3, 2, 2, 3, 3, 3, 3, 5, 1, 1, 2, 4, 1, 5, 2, 2, 4, 5, 2, 2, 1, 2, 4, 6, 1, 5, 2, 4, 1, 4, 3, 5, 1, 4, 1, 7, 6, 8, 4, 4, 4, 9, 3, 2, 1, 5, 4, 9, 2, 2, 2, 3, 2, 8, 6, 9, 1, 1, 1, 2, 4, 8, 3, 1, 4, 7, 8, 8, 2, 3, 3, 3, 1, 8, 1, 2, 3, 10, 10

Offset

0,4

Comments

The positions n, in which a(n)=1: 0, 1, 2, 14, 15, 18, 26, 30, 34, 38, 40, 50, 62, 63, 64, 69, 78, 80, ...

By convention, a(0)=1 as this applies also to the tables A225630 and A225640, whose columns start from zero.

In other words, a(n) = 1 + distance from the first common term on column n (A226055(n)) of tables A225630 and A225640 to the respective fixed point, A003418(n).

Links

Table of n, a(n) for n=0..84.

Formula

a(n) = A225634(n)-A225638(n) = A225644(n)-A225639(n).

Example

Row 7 of A225632 is:
1, 12, 84, 420;
Row 7 of A225642 is:
7, 84, 420;
the last two terms (84 and 420) are common to them, thus a(7)=2.
Row 14 of A225632 is:
1, 84, 1260, 16380, 180180, 360360;
Row 14 of A225642 is:
14, 630, 8190, 90090, 360360;
they have no common term until as the last term of those rows (which is A003418(14)=360360), thus a(14)=1.

Prog

(Scheme):
(define (A226056 n) (- (A225634 n) (A225638 n)))
(define (A226056 n) (- (A225644 n) (A225639 n))) ;; Alternative definition.

Crossrefs

Cf. A226055, A225634, A225644, A225638, A225639.

Sequence in context: A129654 A116504 A186233 * A104011 A242879 A176775

Adjacent sequences: A226053 A226054 A226055 * A226057 A226058 A226059

Keyword

nonn

Author

Antti Karttunen, May 24 2013

Status

approved