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A226056
a(n) = Number of common trailing terms on the row n of tables A225632 and A225642.
10
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).
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
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 24 2013
STATUS
approved