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A103178
Number of divisors of the decimal concatenation of the first n primes.
0
2, 2, 4, 2, 8, 8, 4, 8, 8, 8, 32, 24, 8, 16, 8, 16, 16, 16, 4, 8, 8, 16, 8, 24, 16, 64, 4, 32, 8, 128, 32, 32, 128, 128, 192, 16, 16, 64, 16, 768, 8, 48, 256, 128
OFFSET
1,1
FORMULA
a(n) = A000005(A019518(n)).
EXAMPLE
The number of divisors of 2 is 2, so the first term is 2.
The number of divisors of 23 is 2, so the second term is 2.
The number of divisors of 235 is 4, so the third term is 4.
MATHEMATICA
Table[DivisorSigma[0, FromDigits[Flatten[Table[IntegerDigits[Prime[j]], {j, 1, n}], 1]]], {n, 1, 100}] (* Labos Elemer, Mar 18 2005 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Mar 17 2005
EXTENSIONS
More terms from Labos Elemer, Mar 18 2005
Extended and edited by Charles R Greathouse IV, Apr 25 2010
STATUS
approved