OFFSET
1,1
COMMENTS
Conjecture : every member is a prime.
EXAMPLE
a(6) = 23 is the smallest number coprime to 16,17,18,19,20 and 21. - R. J. Mathar, Sep 02 2008
MAPLE
A000217 := proc(n) n*(n+1)/2 ; end: A077128 := proc(n) option remember ; local ts, a, goodk, k ; if n = 1 then RETURN(2) ; fi; ts := [seq(A000217(n-1)+i, i=1..n)] ; for a from procname(n-1)+1 do goodk := true ; for k in ts do if gcd(a, k) <> 1 then goodk := false; break ; fi; od: if goodk then RETURN(a) ; fi; od: end: for n from 1 to 100 do printf("%d, ", A077128(n)) ; od: # R. J. Mathar, Sep 02 2008
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Oct 29 2002
EXTENSIONS
Extended beyond a(10) by R. J. Mathar, Sep 02 2008
STATUS
approved