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Nonparametric solutions to problem in A027669: n such that for some m, the sum of the first m n-gonal numbers is again an n-gonal number.
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%I #10 Aug 06 2024 01:55:23

%S 3,4,6,8,10,11,14,17,30,41,43,50,60,88,145,276,322,374,823,1152

%N Nonparametric solutions to problem in A027669: n such that for some m, the sum of the first m n-gonal numbers is again an n-gonal number.

%F The parametric solution: if n=2 mod 3, the sum of the first (n^2-4*n-2)/3 n-gonal numbers is the ((n^3-6*n^2+3*n+19)/9)-th n-gonal number.

%Y Cf. A027669.

%K nonn,more

%O 0,1

%A Masanobu Kaneko (mkaneko(AT)math.kyushu-u.ac.jp)

%E More terms from Masanobu Kaneko (mkaneko(AT)math.kyushu-u.ac.jp), Jan 05 1998