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A332271
a(n) is the smallest positive integer that is not a divisor of the n-th highly composite number (A002182).
0
2, 3, 3, 4, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 9, 8, 9, 11, 11, 11, 11, 11, 11, 11, 13, 11, 11, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 17, 16, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 19, 17, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 23, 19, 19, 23, 23, 19, 23
OFFSET
1,1
COMMENTS
a(1)=2 and a(2)=3 are the only terms greater than the n-th highly composite number.
Terms are powers of primes (A000961). - David A. Corneth, Jul 12 2020
LINKS
Matthew Doucette, Highly Composite Numbers (Anti-Primes) (first missing number from factorizations)
Matthew Doucette, Calculating Highly Composite Numbers (Anti-Primes) (first missing number from factorizations)
FORMULA
a(n) = A007978(A002182(n)).
EXAMPLE
a(1) = 2 = least non-divisor of 1.
a(2) = 3 = least non-divisor of 2.
a(3) = 3 = least non-divisor of 4.
a(4) = 4 = least non-divisor of 6.
a(5) = 5 = least non-divisor of 12.
...
PROG
(PARI) nondiv(n) = {for (k=1, n+1, if (n % k, return (k)); ); } \\ A007978
lista(nn) = {my(list=List([1]), r=1); forstep(n=2, nn, 2, if(numdiv(n)>r, r=numdiv(n); listput(list, n)); ); apply(x->nondiv(x), Vec(list)); } \\ Michel Marcus, Jun 10 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Matthew Doucette, Jun 05 2020
EXTENSIONS
a(67)-a(71) from David A. Corneth, Jul 12 2020
STATUS
approved