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!)
A226363 Oblong numbers (A002378) whose sum of divisors is also an oblong number. 1
6, 20, 30, 306, 1722, 2862, 11772, 13572, 28730, 29756, 40602, 54056, 219492, 351056, 463080, 947702, 1391220, 1546292, 2043470, 7174362, 7703400, 11400752, 15104882, 19127502, 20155610, 113667582, 172173762, 314299712, 475654290, 555238532, 558447792, 562519806 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..200

MATHEMATICA

oblongQ[n_] := IntegerQ[(-1 + Sqrt[1 + 4*n])/2]; s = Select[Range[24000], oblongQ[DivisorSigma[1, # (# + 1)]] &]; s * (s + 1) (* T. D. Noe, Jun 12 2013 *)

CROSSREFS

Cf. A000203, A002378, A083674.

Sequence in context: A242341 A140738 A325593 * A253906 A031005 A106528

Adjacent sequences:  A226360 A226361 A226362 * A226364 A226365 A226366

KEYWORD

nonn

AUTHOR

Alex Ratushnyak, Jun 05 2013

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 May 28 15:04 EDT 2022. Contains 354115 sequences. (Running on oeis4.)