login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A239629 Factored over the Gaussian integers, the least positive number having n prime factors, including units -1, i, and -i. 2
1, 2, 5, 10, 30, 130, 390, 2730, 13260, 64090, 192270, 1345890, 7113990, 49797930, 291673590, 2041715130 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Here -1, i, and -i are counted as factors. The factor 1 is counted only in a(1).

Indices of records of A239627. - Amiram Eldar, Jun 27 2020

LINKS

Table of n, a(n) for n=1..16.

MATHEMATICA

nn = 12; t = Table[0, {nn}]; n = 0; found = 0; While[found < nn, n++; cnt = Length[FactorInteger[n, GaussianIntegers -> True]]; If[cnt <= nn && t[[cnt]] == 0, t[[cnt]] = n; found++]]; t

CROSSREFS

Cf. A001221, A001222 (integer factorizations).

Cf. A078458, A086275 (Gaussian factorizations).

Cf. A239627 (number of Gaussian factors of n, including units).

Cf. A239628 (similar to this sequence, but count all prime factors).

Cf. A239630 (number of distinct factors, excluding units).

Sequence in context: A101957 A047113 A239630 * A155580 A226963 A018386

Adjacent sequences:  A239626 A239627 A239628 * A239630 A239631 A239632

KEYWORD

nonn,more,changed

AUTHOR

T. D. Noe, Mar 31 2014

EXTENSIONS

a(14)-a(16) from Amiram Eldar, Jun 27 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 5 20:21 EDT 2020. Contains 335473 sequences. (Running on oeis4.)