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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
OFFSET
1,1
LINKS
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
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Jun 05 2013
STATUS
approved