%N Frobenius number of the numerical semigroup generated by four consecutive tetrahedral numbers.
%C The Frobenius number of a numerical semigroup generated by relatively prime integers a_1,...,a_n is the largest positive integer that is not a nonnegative linear combination of a_1,...,a_n. Since four consecutive tetrahedral numbers are relatively prime, they generate a numerical semigroup with a Frobenius number.
%D R. Froberg, C. Gottlieb and R. Haggkvist, "On numerical semigroups", Semigroup Forum, 35 (1987), 63-83 (for definition of Frobenius number).
%H Harvey P. Dale, <a href="/A069761/b069761.txt">Table of n, a(n) for n = 2..100</a>
%e a(2)=41 because 41 is not a nonnegative linear combination of 4, 10, 20 and 35, but all integers greater than 43 are.
%t FrobeniusNumber/@Partition[Binomial[Range[2,50]+2,3],4,1] (* _Harvey P. Dale_, Jan 22 2012 *)
%Y Cf. A000292, A037165, A059769, A069755-A069764.
%A Victoria A Sapko (vsapko(AT)canes.gsw.edu), Apr 09 2002
%E Sequence terms corrected and extended by Harvey P. Dale, Jan 22 2012
%E Offset corrected and example corrected by Harvey P. Dale, Jan 24 2012