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A125736
a(n)=IntegerLog(n-1)+IntegerLog(n+1), where IntegerLog(n)=A001414(n).
1
6, 8, 9, 12, 11, 13, 13, 17, 14, 24, 16, 21, 17, 25, 16, 36, 17, 29, 22, 33, 22, 33, 24, 19, 26, 38, 21, 60, 20, 45, 29, 26, 29, 49, 31, 53, 32, 57, 23, 84, 27, 54, 40, 58, 36, 61, 23, 34, 29, 73, 28, 69, 24, 38, 44, 81, 43, 120, 45, 74, 45, 31, 28, 85, 37, 93, 35, 97, 26, 144
OFFSET
3,1
EXAMPLE
a(3)=ilog(2)+ilog(4)=(2*1)+(2*2)=6.
a(13)=ilog(12)+ilog(14)=(2*2+3*1)+(2*1+7*1)=16.
MATHEMATICA
iLn = Dot @@ Transpose[FactorInteger[ # ]] &; NiLn = iLn[ # - 1] + iLn[ # + 1] &; Map[NiLn, Range[3, 200]]
CROSSREFS
Sequence in context: A123704 A045574 A074284 * A030725 A195101 A337381
KEYWORD
nonn
AUTHOR
Carlos Alves, Dec 02 2006
STATUS
approved