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Numbers that are both 11-gonal numbers (A051682) and 11-gonal pyramidal numbers (A007586).
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%I #25 May 17 2021 08:50:04

%S 0,1,23725,1519937678700,7248070597636

%N Numbers that are both 11-gonal numbers (A051682) and 11-gonal pyramidal numbers (A007586).

%C Intersection of A051682 and A007586.

%H Numberphile, <a href="https://www.numberphile.com/cannon-ball-numbers">Cannon Ball Numbers</a>.

%o (PARI) for(k=0, 1e5, if(ispolygonal(m=k*(k+1)*(3*k-2)/2, 11), print1(m", ")))

%Y Cf. A007586, A027568, A051682, A344280, A344376.

%K nonn,more

%O 1,3

%A _Seiichi Manyama_, May 17 2021