[seqfan] Naming issue

Veikko Pohjola veikko at nordem.fi
Sun Dec 18 15:28:35 CET 2011

Dear seqfans,


Much what holds for the sequence of twin primes seems to find its neat analogue in another sequence where 'prime' has been replaced by 'semiprime triple'. I encountered a problem when naming such a sequence having recently submitted one, analogous to A001359 (Lesser of twin primes). 


I have used "twin semiprime-triple" as the name of the term because it is the shortest that I found and because it retains the analogy to twin prime. To make sure that "semiprime" and "triple" are understood to belong together and to refer to the whole of a semiprime sandwiched between two semiprimes, I inserted a dash in between.


The definition of twin semiprime-triple would be: a pair of consequent semiprime triples whose center numbers differ by 4, and which are separated by a non-semiprime always divisible by 36. 


I would appreciate your comments on this naming issue.


Veikko Pohjola

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