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\iteman{ZMATH 1993f.03072}
\itemau{Subramaniam, K.B.}
\itemti{A simple computation of square-triangular numbers.}
\itemso{Int. J. Math. Educ. Sci. Technol. 23, No. 5, 790-793 (1992).}
\itemab
The triangular numbers which are also perfect squares are known as square-triangular numbers (STN). First, the proof of the following theorem is given: If a sup(2)(n) denotes the nth STN then for n greater as equal 3 a(n) = 6 a(n-1) - a(n-2) while a(1)=1, a(2)=6. The second result aims at the index of the triangular number which is a STN: If T(p) is the pth triangular number which is also the nth STN, then p = Ksup(2)(n) - (1+(-1)sup(n))/2 where K(1)=1, K(2)=3 and K(and K(n) = 2 K(n-1) + K(n-2) for n greater as equal 3.
\itemrv{~}
\itemcc{F60}
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\itemli{}
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