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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 (list; graph; refs; listen; history; text; internal format)
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

Table of n, a(n) for n=1..71.

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)

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

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

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Last modified September 24 17:09 EDT 2020. Contains 337321 sequences. (Running on oeis4.)