OFFSET
0,1
COMMENTS
Conjecture: There is no -1 in this sequence.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..10000 (first 516 terms from Nicolas Bělohoubek)
FORMULA
It appears that the sequence satisfies these rules, for large m:
Rule 1: a(prime(m+1) - 2) = prime(m+1)
Rule 2: a(prime(m+1) - 1) = 3*prime(m+1)
Rule 3: a(prime(m+1) + 1) = 5*prime(m+1)
Rule 4: a(prime(m+1) - 3) = 6*prime(m+1)
Rule 5: a(prime(m+1) + 3) = 7*prime(m+1)
Rule 6: a(prime(m+1)) = 9*prime(m+1)
Rule 7: a(prime(m+1) - 7) = 11*prime(m+1)
Rule 8: a(prime(m+1) + 7) = 12*prime(m+1)
Rule 9: a(prime(m+1) + 9) = 13*prime(m+1)
...
Choose the first rule that applies.
PROG
(PARI) f(m) = my(fp=factor(m)); sum(k=1, #fp~, fp[k, 1]*fp[k, 2]) - numdiv(fp);
a(n) = my(k=2); while(f(k) != n, k++); k; \\ Michel Marcus, Apr 06 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Nicolas Bělohoubek, Apr 05 2022
STATUS
approved