The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A090466 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A090466

Regular figurative or polygonal numbers of order greater than 2.
(history; published version)

#98 by Susanna Cuyler at Sat May 08 23:00:16 EDT 2021

STATUS

proposed

approved

#97 by Jon E. Schoenfield at Sat May 08 19:02:41 EDT 2021

STATUS

editing

proposed

#96 by Jon E. Schoenfield at Sat May 08 19:02:39 EDT 2021

FORMULA

Integer n k is in this sequence iff A176774(nk) < nk. - Max Alekseyev, Apr 24 2018

CROSSREFS

Sequence A090428 (excluding 1) is a subset subsequence of this sequence. - T. D. Noe, Jun 14 2012

STATUS

approved

editing

#95 by Peter Luschny at Sun Mar 14 12:34:33 EDT 2021

STATUS

reviewed

approved

#94 by Joerg Arndt at Sun Mar 14 12:22:29 EDT 2021

STATUS

proposed

reviewed

#93 by Jianing Song at Sun Mar 14 12:11:20 EDT 2021

STATUS

editing

proposed

#92 by Jianing Song at Sun Mar 14 12:10:47 EDT 2021

COMMENTS

Numbers m such that r = (2*m/d - 2)/(d - 1) is an integer for some d, where 2 < d < m is a divisor of 2*m. If r is an integer, then m is the d-th (r+2)-gonal number. - Jianing Song, Mar 14 2021

STATUS

proposed

editing

#91 by Jianing Song at Sun Mar 14 12:07:40 EDT 2021

STATUS

editing

proposed

#90 by Jianing Song at Sun Mar 14 12:06:32 EDT 2021

COMMENTS

Numbers m such that (2*m/d - 2)/(d - 1) is an integer for some d, where 2 < d < m is a divisor of 2*m. - Jianing Song, Mar 14 2021

PROG

(PARI) isA090466(m) = my(v=divisors(2*m)); for(i=3, #v, my(d=v[i]); if(d==m, return(0)); if((2*m/d - 2)%(d - 1)==0, return(1))); 0 \\ Jianing Song, Mar 14 2021

STATUS

approved

editing

Discussion

Sun Mar 14

12:07

Jianing Song: I wonder if my program is a bit faster; if it is not, feel free to remove it.

#89 by Joerg Arndt at Mon Sep 21 10:53:56 EDT 2020

STATUS

reviewed

approved