%I #11 May 21 2021 18:38:39
%S 1,1,2,6,10,12,21,35,36,70,112,117,230,368,390,759,763,1290,2244,2292,
%T 3133,3580,4170,5154,5355,7014,7710,9160,9328,11592,19274,22616,27555,
%U 37290,37312,40756,47820,63680,68862,87450,93730,108985,110262,132888,137731,159159
%N a(0)=a(1)=1, a(n) = least k > a(n-1) such that k*a(n-2) is an oblong number.
%p isA002378 := proc(n)
%p if issqr(1+4*n) then
%p (sqrt(1+4*n)-1) /2 ;
%p type(%,'integer') ;
%p else
%p false;
%p end if;
%p end proc:
%p A214963 := proc(n)
%p option remember;
%p local k ;
%p if n <= 1 then
%p 1;
%p else
%p for k from procname(n-1)+1 do
%p if isA002378(k*procname(n-2)) then
%p return k;
%p end if;
%p end do:
%p end if;
%p end proc: # _R. J. Mathar_, Aug 10 2012
%Y Cf. A002378.
%K nonn
%O 0,3
%A _Alex Ratushnyak_, Aug 03 2012
|