OFFSET
1,1
COMMENTS
A005369(a(n)) = 1.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..301
EXAMPLE
Distribution of oblong numbers on A249406 and its complement,
m*(m+1) factorizations are shown in respective columns:
. ---+---------+---------+-------- ---+---------+---------+--------
. 1 | 2 | | 1*2 13 | 182 | 13*14 |
. 2 | 6 | 2*3 | 14 | 210 | | 14*15
. 3 | 12 | | 3*4 15 | 240 | 15*16 |
. 4 | 20 | 4*5 | 16 | 272 | | 16*17
. 5 | 30 | | 5*6 17 | 306 | 17*18 |
. 6 | 42 | | 6*7 18 | 342 | | 18*19
. 7 | 56 | 7*8 | 19 | 380 | | 19*20
. 8 | 72 | | 8*9 20 | 420 | | 20*21
. 9 | 90 | 9*10 | 21 | 462 | | 21*22
. 10 | 110 | | 10*11 22 | 506 | 22*23 |
. 11 | 132 | 11*12 | 23 | 552 | | 23*24
. 12 | 156 | | 12*13 24 | 600 | 24*25 | .
PROG
(Haskell)
a249411 n = a249411_list !! (n-1)
a249411_list = filter ((== 1) . a005369) a249407_list
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 31 2014
STATUS
approved