A332271 a(n) is the smallest positive integer that is not a divisor of the n-th highly composite number (A002182).
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, 23, 23, 23, 23, 23
Offset: 1
Keywords
Examples
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. ...
Links
- Jason A. Doucette, Table of n, a(n) for n = 1..20000
- Matthew Doucette, Lowest Unused Anti-Prime (Highly Composite Number) Factors
- 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)
Programs
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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
Extensions
a(67)-a(71) from David A. Corneth, Jul 12 2020
a(72) onward from Jason A. Doucette, Jul 20 2025
Comments