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A123134
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a(n) = prime(n)*(prime(n+1) + 1).
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5
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8, 18, 40, 84, 154, 234, 340, 456, 690, 928, 1178, 1554, 1804, 2064, 2538, 3180, 3658, 4148, 4824, 5254, 5840, 6636, 7470, 8722, 9894, 10504, 11124, 11770, 12426, 14464, 16764, 18078, 19180, 20850, 22648, 23858, 25748, 27384, 29058, 31140, 32578
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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EXAMPLE
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a(1) = 2*(3+1) = 8, a(2) = 3*(5+1) = 18, a(3) = 5*(7+1) = 40, ...
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MATHEMATICA
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a[n_]:=Prime[n](Prime[n+1]+1); Array[a, 80] (* Giovanni Resta, Apr 02 2017 *)
#[[1]](#[[2]]+1)&/@Partition[Prime[Range[50]], 2, 1] (* Harvey P. Dale, Jan 06 2019 *)
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PROG
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(PARI) for(n=1, 100, print1(prime(n)*(prime(n+1)+1), ", "))
(Python)
from sympy import prime
def a(n): return prime(n) * (prime(n + 1) + 1) # Indranil Ghosh, Apr 02 2017
(Magma) [NthPrime(n)*(NthPrime(n+1) +1): n in [1..40]]; // G. C. Greubel, Aug 04 2021
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 30 2006
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STATUS
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approved
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