login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A295644 Rectangular array, by antidiagonals; row 1 is the ordered list of all k having at most 2 unitary divisors; for n > 1, row n is the ordered list of all k having 2^n unitary divisors. 1
1, 2, 6, 3, 10, 30, 4, 12, 42, 210, 5, 14, 60, 330, 2310, 7, 15, 66, 390, 2730, 30030, 8, 18, 70, 420, 3570, 39270, 510510, 9, 20, 78, 462, 3990, 43890, 570570 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Every positive integer occurs exactly once, so that as a sequence, this is a permutation of the positive integers.
row 1: A000961
row 2: A007774
row 3: A033992
row 4: A033993
col 1: A231209
LINKS
EXAMPLE
Northwest corner:
1 2 3 4 5 7 8 9 11
6 10 12 14 15 18 20 21 22
30 42 60 66 70 78 84 90 102
210 330 390 420 462 510 546 570 630
2310 2730 3570 3990 4290 4620 4830 5460 5610
MATHEMATICA
z = 10000;
t = Table[2^PrimeNu[n], {n, 1, z}] ; (* A035555 *)
r[n_] := Flatten[Position[t, 2^n]]; r[1] = Join[{1}, r[1]];
v[n_, k_] := r[n][[k]];
TableForm[Table[v[n, k], {n, 1, 5}, {k, 1, 15}]] (* A295644 array *)
Table[v[n - k + 1, k], {n, 5}, {k, n, 1, -1}] // Flatten (* A295644 sequence *)
CROSSREFS
Cf. A034444.
As an array, essentially the same as A125666.
Sequence in context: A277810 A180428 A130684 * A079178 A322365 A297553
KEYWORD
nonn,tabl,more
AUTHOR
Clark Kimberling, Jun 26 2018
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 13 09:39 EDT 2024. Contains 374274 sequences. (Running on oeis4.)