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A068108 a(1) = 1; a(n+1) = sum{k|n k<=sqrt(n)} a(k) where sum is over the positive divisors k of n with k <= sqrt(n). 4
1, 1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 3, 1, 3, 1, 3, 2, 2, 1, 4, 3, 2, 2, 3, 1, 5, 1, 3, 2, 2, 3, 5, 1, 2, 2, 5, 1, 4, 1, 3, 4, 2, 1, 5, 3, 4, 2, 3, 1, 4, 3, 5, 2, 2, 1, 7, 1, 2, 4, 4, 3, 4, 1, 3, 2, 6, 1, 6, 1, 2, 4, 3, 3, 4, 1, 6, 4, 2, 1, 7, 3, 2, 2, 4, 1, 8, 3, 3, 2, 2, 3, 6, 1, 4, 4, 7, 1, 4, 1, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
LINKS
FORMULA
a(n) = A038548(n-1), 2<=n<=25. - Omar E. Pol, Feb 05 2014
MATHEMATICA
a[1]=1; a[n_] := a[n] = Module[{d=Divisors[n-1], s=0, i=1}, While[i<=Length[d] && d[[i]]<=Sqrt[n-1], s=s+a[d[[i]]]; i++ ]; s]; Table[a[n], {n, 150}] (T. D. Noe)
CROSSREFS
Different from A038548.
Sequence in context: A336737 A327400 A323303 * A342679 A337135 A113309
KEYWORD
nonn
AUTHOR
Leroy Quet, Mar 22 2002
EXTENSIONS
More terms from T. D. Noe, Nov 03 2004
STATUS
approved

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Last modified March 28 16:28 EDT 2024. Contains 371254 sequences. (Running on oeis4.)