OFFSET
1,2
LINKS
Daniel Suteu, Table of n, a(n) for n = 1..21
FORMULA
PROG
(PARI) L(n)=fibonacci(n+1)+fibonacci(n-1); \\ A000032
isld(n) = { my(u1=1, u2=3, old_u1); if(n<=2, sign(n), while(n>u2, old_u1=u1; u1=u2; u2=old_u1+u2); (u2==n)); }; \\ A102460
nbld(n) = sumdiv(n, d, isld(d)); \\ A304092
a(n) = my(k=0); while(nbld(L(k)) != n, k++); L(k);
(PARI)
countLd(n) = my(c=0, x=2, y=1); while(x <= n, if(n%x == 0, c++); [x, y]=[y, x+y]); c;
a(n) = if(n==1, return(1)); my(x=2, y=1); while(1, if(countLd(x) == n, return(x)); [x, y]=[y, x+y]); \\ Daniel Suteu, Aug 24 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Jul 27 2022
EXTENSIONS
a(11) from Daniel Suteu, Aug 06 2022
STATUS
approved