OFFSET
0,2
EXAMPLE
a(1) = 3: 3 = 1+2;
a(2) = 12: 1*5*12 = 2+3+4+6+7+8+9+10+11, 2*4*8 = 1+3+5+6+7+9+10+11+12;
a(3) = 10: 1*2*3*7 = 4+5+6+8+9+10, 1*4*10 = 2+3+5+6+7+8+9, 6*7 = 1+2+3+4+5+8+9+10.
PROG
(Haskell)
import Data.List (elemIndex)
import Data.Maybe (fromJust)
a207852 n = (fromJust $ elemIndex n a178830_list) + 1
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Feb 21 2012
EXTENSIONS
a(25)-a(54) from Alois P. Heinz, Jun 07 2012
STATUS
approved