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 A216356 a(n) = A000172(n^2), where Franel number A000172(n) = Sum_{k=0..n} C(n,k)^3. 1
 1, 2, 346, 5280932, 6332299624282, 548057409594239814752, 3282684865686445066146128050420, 1329153351023643434414727317328867397924832, 35862023917618878200052422822926970148356592776600354650, 63875599229358329592315180101212796802405282289343043273094466311541144 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA Forms the logarithmic derivative of A216355 after ignoring initial term a(0). EXAMPLE L.g.f.: L(x) = 2*x + 346*x^2/2 + 5280932*x^3/3 + 6332299624282*x^4/4 + 548057409594239814752*x^5/5 +... where exp(L(x)) = 1 + 2*x + 175*x^2 + 1760658*x^3 + 1583078442003*x^4 + 109611485085305859618*x^5 +...+ A216355(n)*x^n +... PROG (PARI) {a(n)=sum(k=0, n^2, binomial(n^2, k)^3)} for(n=0, 15, print1(a(n), ", ")) CROSSREFS Cf. A216355, A166990, A216352, A216353, A216354, A000172. Sequence in context: A248172 A064501 A063831 * A064023 A179959 A024350 Adjacent sequences:  A216353 A216354 A216355 * A216357 A216358 A216359 KEYWORD nonn AUTHOR Paul D. Hanna, Sep 04 2012 STATUS approved

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Last modified April 8 21:34 EDT 2020. Contains 333329 sequences. (Running on oeis4.)