OFFSET
1,2
LINKS
EXAMPLE
. n | divisors | . . . in binary | a(n)
. ---+----------------+---------------------------+--------------------
. 10 | 1,2,5,10 | 1,10,101,1010 | 2 + 10 | 12
. 11 | 1,11 | 1,1011 | 1 + 11 | 12
. 12 | 1,2,3,4,6,12 | 1,10,11,100,110,1100 | 4 + 12 | 16
. 13 | 1,13 | 1,1101 | 1 + 13 | 14
. 14 | 1,2,7,14 | 1,10,111,1110 | 2 + 14 | 16
. 15 | 1,3,5,15 | 1,11,101,1111 | 1 + 3 + 15 | 19
. 16 | 1,2,4,8,16 | 1,10,100,1000,10000 | 16 | 16
. 17 | 1,17 | 1,10001 | 1 + 17 | 18
. 18 | 1,2,3,6,9,18 | 1,10,11,110,1001,10010 | 2 + 18 | 20
. 19 | 1,19 | 1,10011 | 1 + 19 | 20
. 20 | 1,2,4,5,10,20 | 1,10,100,101,1010,10100 | 4 + 20 | 24;
a(63) = 1 + 3 + 7 + 63 = 74;
a(735) = 1 + 3 + 7 + 15 + 735 = 761;
a(4095) = 1 + 3 + 7 + 15 + 63 + 4095 = 4185;
a(185535) = 1 + 3 + 7 + 15 + 31 + 63 + 185535 = 185655.
PROG
(Haskell)
import Data.List (isPrefixOf); import Data.Function (on)
a239826 n = sum $
filter ((flip isPrefixOf `on` a030308_row) n) $ a027750_row n
-- Reinhard Zumkeller, Mar 27 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 27 2014
STATUS
approved