login
A230034
Numbers which can't be represented as a sum of 3 relatively prime positive integers such that each pair of them is not coprime.
3
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 51, 52, 54, 56, 57, 58, 60, 62, 63, 64, 66, 68, 70, 72, 74, 75, 76, 78
OFFSET
1,2
COMMENTS
Complement of A230035.
Sequence is finite and contains exactly 156 terms.
Generally for every positive integer k there is only a finite quantity of numbers which can't be represented as a sum of k + 1 relatively prime positive integers such that any k of them are not coprime.
For instance, for k = 3, 570570 is the largest number which cannot be represented.
LINKS
Vladimir Letsko, Table of n, a(n) for n = 1..156 [uploaded as b-file by Georg Fischer, Aug 24 2020]
Vladimir Letsko, Table of n, a(n) for n=1..156 (full sequence, source for b-file)
EXAMPLE
Every positive integer less than 31 is in the sequence because 31 obviously is the least number which can be represented as 2*3 + 2*5 + 3*5, i.e. as a sum of 3 relatively prime positive integers such that every pair of them is not coprime.
CROSSREFS
Cf. A230035.
Sequence in context: A247064 A160547 A348520 * A269331 A246103 A281873
KEYWORD
nonn,fini,full
AUTHOR
Vladimir Letsko, Dec 20 2013
STATUS
approved