The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A211515 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing all changes.

A211515

Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^3=x*y.
(history; published version)

#10 by Peter Luschny at Sat Oct 17 11:36:59 EDT 2020

STATUS

reviewed

approved

#9 by Michel Marcus at Sat Oct 17 10:56:45 EDT 2020

STATUS

proposed

reviewed

#8 by Ridouane Oudra at Sat Oct 17 09:16:53 EDT 2020

STATUS

editing

proposed

#7 by Ridouane Oudra at Sat Oct 17 09:16:44 EDT 2020

CROSSREFS

Cf. A211422, A010057.

STATUS

proposed

editing

#6 by Ridouane Oudra at Sat Oct 17 09:15:51 EDT 2020

STATUS

editing

proposed

#5 by Ridouane Oudra at Sat Oct 17 09:12:56 EDT 2020

FORMULA

a(n) = Sum_{i=1..n} Sum_{j=1..n} A010057(i*j). - Ridouane Oudra, Oct 17 2020

STATUS

approved

editing

#4 by T. D. Noe at Sat Apr 21 12:13:46 EDT 2012

STATUS

proposed

approved

#3 by Clark Kimberling at Sat Apr 21 12:00:47 EDT 2012

STATUS

editing

proposed

#2 by Clark Kimberling at Sat Apr 14 10:54:07 EDT 2012

NAME

allocated for Clark KimberlingNumber of ordered triples (w,x,y) with all terms in {1,...,n} and w^3=x*y.

DATA

0, 1, 1, 1, 3, 3, 3, 3, 6, 8, 8, 8, 8, 8, 8, 8, 10, 10, 12, 12, 12, 12, 12, 12, 14, 16, 16, 21, 21, 21, 21, 21, 25, 25, 25, 25, 27, 27, 27, 27, 29, 29, 29, 29, 29, 29, 29, 29, 31, 33, 35, 35, 35, 35, 39, 39, 41, 41, 41, 41, 41, 41, 41, 41, 48, 48, 48, 48, 48, 48, 48

OFFSET

0,5

COMMENTS

For a guide to related sequences, see A211422.

MATHEMATICA

t[n_] := t[n] = Flatten[Table[w^3 - x*y, {w, 1, n}, {x, 1, n}, {y, 1, n}]]

c[n_] := Count[t[n], 0]

t = Table[c[n], {n, 0, 70}] (* A211515 *)

CROSSREFS

Cf. A211422.

KEYWORD

allocated

nonn

AUTHOR

Clark Kimberling, Apr 14 2012

STATUS

approved

editing

#1 by Clark Kimberling at Fri Apr 13 17:53:40 EDT 2012

NAME

allocated for Clark Kimberling

KEYWORD

allocated

STATUS

approved