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A333613
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a(1) = 1; thereafter a(n) = Sum_{k = 1..n} a(k/gcd(n,k)).
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2
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1, 2, 4, 7, 15, 21, 51, 78, 158, 230, 568, 661, 1797, 2595, 5117, 7789, 19095, 21702, 59892, 81801, 171329, 258028, 630942, 713093, 1887828, 2776798, 5727675, 8335692, 20702970, 21420664, 62826604, 92041835, 189376593, 281410640, 656577018, 742729123, 2087788417
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OFFSET
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1,2
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LINKS
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FORMULA
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a(1) = 1; a(n) = Sum_{k = 1..n} a(lcm(n, k)/n).
a(1) = 1; a(n) = Sum_{d|n} Sum_{k = 1..d, gcd(d, k) = 1} a(k).
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MAPLE
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if n<3 then n;
else add( A333613(lcm(n, j)/n), j = 1..n);
end if; end proc;
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = Sum[a[k/GCD[n, k]], {k, n}]; Table[a[n], {n, 37}]
a[1] = 1; a[n_] := a[n] = Sum[Sum[If[GCD[k, d] == 1, a[k], 0], {k, d}], {d, Divisors[n]}]; Table[a[n], {n, 37}]
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PROG
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(Sage)
@CachedFunction
def A333613(n): return 1 if n==1 else sum( A333613(lcm(n, j)/n) for j in (1..n) )
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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