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A075882
a(n) = phi(Sum_{i=1,...,n} prime(i)).
1
1, 4, 4, 16, 12, 40, 28, 60, 40, 84, 64, 196, 96, 280, 160, 252, 160, 332, 280, 420, 352, 672, 396, 636, 416, 756, 624, 912, 576, 1044, 672, 1232, 840, 1416, 1136, 1616, 1152, 2640, 1380, 1764, 1540, 2292, 1696, 2552, 1872, 2816, 1896, 4524, 2208, 4032, 2120
OFFSET
1,2
LINKS
EXAMPLE
The sum of the first three primes = 10 and phi(10) = 4, so a(3) = 4.
MATHEMATICA
Table[EulerPhi[Sum[Prime[k], {k, 1, i}]], {i, 1, 100}]
EulerPhi[Accumulate[Prime[Range[60]]]] (* Harvey P. Dale, Jun 18 2024 *)
CROSSREFS
Sequence in context: A273830 A250069 A333169 * A369891 A125757 A196065
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Oct 16 2002
STATUS
approved