A277216 Product of decimal digits of sum of divisors of n.
1, 3, 4, 7, 6, 2, 8, 5, 3, 8, 2, 16, 4, 8, 8, 3, 8, 27, 0, 8, 6, 18, 8, 0, 3, 8, 0, 30, 0, 14, 6, 18, 32, 20, 32, 9, 24, 0, 30, 0, 8, 54, 16, 32, 56, 14, 32, 8, 35, 27, 14, 72, 20, 0, 14, 0, 0, 0, 0, 48, 12, 54, 0, 14, 32, 16, 48, 12, 54, 16, 14, 45, 28, 4, 8
Offset: 1
Examples
a(12) = 16 because sigma(12) = 28; 2*8 = 16.
Links
- Jaroslav Krizek, Table of n, a(n) for n = 1..1000
Programs
-
Magma
[&*Intseq(SumOfDivisors(n)): n in [1..100000]];
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Maple
seq( convert(convert(numtheory:-sigma(n),base,10),`*`), n=1..100); # Robert Israel, Oct 06 2016
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Mathematica
Table[Times @@ IntegerDigits@ DivisorSigma[1, n], {n, 75}] (* Michael De Vlieger, Oct 06 2016 *) -
PARI
a(n) = d = digits(sigma(n)); prod(k=1, #d, d[k]); \\ Michel Marcus, Oct 05 2016
Comments