cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A374374 Oblong numbers that are products of smaller oblong numbers.

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%I A374374 #5 Jul 07 2024 13:51:34
%S A374374 12,72,240,420,600,1056,1260,2352,4032,6480,7140,9120,9900,10920,
%T A374374 14280,14520,18360,20592,20880,28392,38220,46872,50400,65280,78120,
%U A374374 82656,83232,104652,123552,129960,147840,159600,194040,233772,245520,262656,278256,279312
%N A374374 Oblong numbers that are products of smaller oblong numbers.
%C A374374 The oblong number (k^2+2*k)*(k^2+2*k+1) = A047928(k+2) is a term for all k >= 1, because it is the product of the oblong numbers k*(k+1) and (k+1)*(k+2).
%e A374374 72 is a term because 72 = 8*9 = 6*12 = (2*3)*(3*4).
%e A374374 1056 is a term because 1056 = 32*33 = 2*2*2*132 = (1*2)*(1*2)*(1*2)*(11*12). (This is the first term that requires more than two factors.)
%Y A374374 A188660 is a subsequence (only 2 factors allowed).
%Y A374374 Cf. A002378, A047928, A068143, A374375.
%K A374374 nonn
%O A374374 1,1
%A A374374 _Pontus von Brömssen_, Jul 07 2024