

A191914


Smallest number m greater than n such that the happy couples of m and n have a member in common.


2



2, 3, 5, 6, 7, 8, 10, 12, 12, 11, 13, 15, 17, 18, 20, 20, 19, 22, 23, 24, 28, 32, 26, 28, 30, 27, 29, 35, 31, 35, 37, 34, 39, 38, 42, 42, 41, 40, 52, 46, 43, 48, 47, 52, 55, 54, 50, 56, 56, 51, 53, 60, 58, 62, 70, 63, 69, 59, 61, 68, 65, 66, 72, 72, 67, 86
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

The intersection of {A007966(n),A007967(n)} and {A007966(a(n)),A007967(a(n))} is not empty, but the intersection of {A007966(n),A007967(n)} and {A007966(m),A007967(m)} is empty for n<m<a(n).


LINKS

Table of n, a(n) for n=1..66.
J. H. Conway, On Happy Factorizations, J. Integer Sequences, Vol. 1, 1998, #1.


EXAMPLE

Let hc(n) = (A007966(n),A007967(n)),
n=6, a(6) = 8: hc(6) = (2,3) and hc(8) = (2,4) with common 2,
n=7, a(7) = 10: hc(7) = (7,1) and hc(10) = (1,10) with common 1,
n=8, a(8) = 12: hc(8) = (2,4) and hc(12) = (3,4) with common 4,
n=9, a(9) = 12: hc(9) = (3,3) and hc(12) = (3,4) with common 3.


CROSSREFS

Sequence in context: A181807 A059870 A179813 * A329898 A145353 A013936
Adjacent sequences: A191911 A191912 A191913 * A191915 A191916 A191917


KEYWORD

nonn


AUTHOR

Reinhard Zumkeller, Jun 19 2011


STATUS

approved



