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A172034
Partial sums of Pillai primes (A063980).
0
23, 52, 111, 172, 239, 310, 389, 472, 581, 718, 857, 1006, 1199, 1426, 1659, 1898, 2149, 2406, 2675, 2946, 3223, 3516, 3823, 4134, 4451, 4810, 5189, 5572, 5961, 6358, 6759, 7178, 7609, 8058, 8519, 8982, 9449, 9928, 10427, 10930, 11451, 12008, 12571
OFFSET
1,1
COMMENTS
The values alternate between odd and even. The first prime partial sum of Pillai primes is a(5) = 23 + 29 + 59 + 61 + 67 = 239. The second prime partial sum is a(7) = 389. The next such primes are a(11) = 857 (= the 72nd Pillai prime), a(23) = 3823, a(25) = 4451, a(27) = 5189. The coincidence which prompted this sequence is that the 266th Pillai prime is a(23), the sum of the first 23 Pillai primes. Curiously, 23 is the smallest Pillai prime. What are the next such Pillai primes in the partial sum?
FORMULA
a(n) = SUM[i=i..n]A063980(i) = SUM[i=i..n] {p: p prime and there exists an integer m such that m!+1 is 0 mod p and p is not 1 mod m}.
EXAMPLE
a(1) = 23 because 23 is the first Pillai prime A063980(1). a(2) = 52 because 23+29 = 52 is the sum of the first two Pillai primes A063980(1)+A063980(2).
CROSSREFS
Sequence in context: A165432 A067625 A140689 * A335655 A113912 A327920
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Jan 23 2010
EXTENSIONS
More terms from R. J. Mathar, Jan 24 2010
STATUS
approved