A037165 a(n) = prime(n)*prime(n+1) - prime(n) - prime(n+1).
1, 7, 23, 59, 119, 191, 287, 395, 615, 839, 1079, 1439, 1679, 1931, 2391, 3015, 3479, 3959, 4619, 5039, 5615, 6395, 7215, 8447, 9599, 10199, 10811, 11447, 12095, 14111, 16379, 17679, 18767, 20423, 22199, 23399, 25271, 26891, 28551, 30615, 32039
Offset: 1
Links
- Joshua Oliver, Table of n, a(n) for n = 1..2000 (first 1000 terms from Vincenzo Librandi)
- R. Fröberg, C. Gottlieb and R. Häggkvist, On numerical semigroups, Semigroup Forum, 35 (1987), 63-83 (for definition of Frobenius number).
Crossrefs
Programs
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Magma
[NthPrime(n)*NthPrime(n+1)-NthPrime(n)-NthPrime(n+1): n in [1..45]]; // Vincenzo Librandi, Dec 18 2012
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Mathematica
f[n_] := FrobeniusNumber[{Prime[n], Prime[n + 1]}]; Array[f, 41] (* Robert G. Wilson v, Aug 04 2012 *) Times@@#-Total[#]&/@Partition[Prime[Range[50]],2,1] (* Harvey P. Dale, Dec 27 2015 *)
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PARI
a(n)=my(p=prime(n),q=nextprime(p+1)); p*q-p-q \\ Charles R Greathouse IV, Apr 28 2015
Comments