

A332271


a(n) is the smallest positive integer that is not a divisor of the nth 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
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OFFSET

1,1


COMMENTS

a(1)=2 and a(2)=3 are the only terms greater than the nth highly composite number.
Terms are powers of primes (A000961).  David A. Corneth, Jul 12 2020


LINKS

Table of n, a(n) for n=1..71.
Matthew Doucette, Lowest Unused AntiPrime (Highly Composite Number) Factors
Matthew Doucette, Highly Composite Numbers (AntiPrimes) (first missing number from factorizations)
Matthew Doucette, Calculating Highly Composite Numbers (AntiPrimes) (first missing number from factorizations)


FORMULA

a(n) = A007978(A002182(n)).


EXAMPLE

a(1) = 2 = least nondivisor of 1.
a(2) = 3 = least nondivisor of 2.
a(3) = 3 = least nondivisor of 4.
a(4) = 4 = least nondivisor of 6.
a(5) = 5 = least nondivisor 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

Cf. A000961, A002182, A007978.
Sequence in context: A196155 A140858 A075458 * A267861 A253548 A083036
Adjacent sequences: A332268 A332269 A332270 * A332272 A332273 A332274


KEYWORD

nonn


AUTHOR

Matthew Doucette, Jun 05 2020


EXTENSIONS

a(67)a(71) from David A. Corneth, Jul 12 2020


STATUS

approved



