

A242926


a(n) = denominator of B(0,n), where B(n,n)=0, B(n1,n)=1/n and otherwise B(m,n)=B(m1,n+1)B(m1,n).


1



1, 1, 1, 2, 1, 6, 1, 4, 3, 5, 1, 4, 1, 7, 15, 8, 1, 18, 1, 10, 21, 11, 1, 24, 5, 13, 9, 14, 1, 30, 1, 16, 11, 17, 35, 12, 1, 19, 39, 20, 1, 42, 1, 22, 9, 23, 1, 48, 7, 25, 17, 26, 1, 54, 55, 28, 19, 29, 1, 20, 1
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OFFSET

0,4


COMMENTS

The numerators are A189731(n).
B(0,n) = 0, 1, 1, 3/2, 2, 17/6, 4, 23/4, 25/3, 61/5, 18, 107/4, 40, 421/7, ...
is a super autosequence as defined in A242563.
The positive integers in B(0,n) give A064723(n). Corresponding rank: A006093(n+1). B(0,n) is linked to the primes A000040.
Divisor of B(0,n), n>0: 1, 1, 1, 2, 2, 4, 5, ... = A172128(n+1).
Common (LCM) denominators for the antidiagonals: 1, 1, 1, 2, 2, 6, 6, 12, 12,... = A139550(n+1)?.
1 = 1
1/2 + 3/2 = 2
1/3 + 5/6 + 17/6 = 4
1/4 + 7/12 + 7/4 + 23/4 = 25/3
etc.
The positive terms of the first bisection are the sum of the corresponding antidiagonal terms upon the 0's.
0 followed by A001610(n) i.e. 0, 0, 2, 3, 6, 10, 17, ... is an autosequence of the second kind.


LINKS

Table of n, a(n) for n=0..60.


FORMULA

a(2n+1) = A175386(n).
Denominators of B(0,n) = A001610(n)/(n+1).


CROSSREFS

Cf. A175386, A001610, A189731, A139550, A242563.
Sequence in context: A285038 A243145 A306695 * A189733 A306927 A277791
Adjacent sequences: A242923 A242924 A242925 * A242927 A242928 A242929


KEYWORD

nonn


AUTHOR

Paul Curtz, May 26 2014


EXTENSIONS

a(24)a(60) from JeanFrançois Alcover


STATUS

approved



