A324541 Numbers that occur in range of A324580.

0, 2, 6, 18, 30, 36, 70, 90, 120, 210, 270, 300, 434, 450, 650, 672, 990, 1050, 1260, 1386, 2142, 2250, 2310, 2590, 2940, 3600, 3990, 4410, 4642, 4750, 5978, 6996, 7350, 7500, 7650, 8190, 9114, 11880, 12600, 14058, 15000, 15050, 15750, 16170, 18480, 18522, 21186, 23100, 23870, 24750, 25830, 28224, 30030, 30870, 31250, 32830, 35970, 37114, 42000

Offset

0,2

Comments

Indexing begins from 0 because the term a(0) = 0 is a special case.

Sequence A324580 sorted into ascending order, with duplicate occurrences removed. The first such duplicate is 2250 = A324580(15) = 150*15 = A324580(18) = 125*18. The next is 5402250 = A324580(105) = A276086(105)*105 = A324580(125) = A276086(125)*125.

Terms after zero are the positions of nonzero terms in A324539.

Links

Antti Karttunen, Table of n, a(n) for n = 0..702

Index entries for sequences related to primorial base

Index entries for sequences related to primorial numbers

Prog

(PARI)
A276086(n) = { my(i=0, m=1, pr=1, nextpr); while((n>0), i=i+1; nextpr = prime(i)*pr; if((n%nextpr), m*=(prime(i)^((n%nextpr)/pr)); n-=(n%nextpr)); pr=nextpr); m; };
A324539(n) = sumdiv(n, d, (d==A276086(n/d)));
for(n=1, oo, if(A324539(n)>0, print1(n, ", "))); \\ Print terms after zero.
(PARI)
\\ This program is better for computing many terms:
search_limit = 9699690;
A324580(n) = n*A276086(n);
A324541list(lim) = { my(s=Set([]), k); for(n=1, lim, k=A324580(n); if(k<=lim, s = setunion([k], s))); Vec(s); };
v324541 = A324541list(search_limit);
A324541(n) = if(!n, n, v324541[n]);

Crossrefs

Cf. A324540 (complement).

Cf. A002110 (a subsequence), A276086, A324539, A324579, A324580.

Sequence in context: A185382 A257065 A066286 * A351875 A197168 A288815

Adjacent sequences: A324538 A324539 A324540 * A324542 A324543 A324544

Keyword

nonn

Author

Antti Karttunen, Mar 10 2019

Status

approved