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 A117693 Row sums of A117692. 1
 1, 6, 42, 27, 480, 265, 7070, 3815, 1820, 1449, 107338, 56903, 4636632, 2635061, 993850, 633919, 71014372, 42899857, 8111619802, 4675943415, 1414861448, 819657397, 113827776894, 75106291091, 41292848428 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS G. C. Greubel, Table of n, a(n) for n = 1..1000 FORMULA a(n) = Sum_{k=1..n} A117692(n, k). MATHEMATICA f[n_]:= If[PrimeQ[n], n, 1]; cf[n_]:= cf[n]= If[n==0, 1, f[n]*cf[n-1]]; (* A034386 *) T[n_, k_]:= T[n, k]= cf[n]^2/(cf[k]*cf[n-k]); a[n_]:= a[n]= Sum[T[n, k], {k, n}]; Table[a[n], {n, 30}] PROG (Magma) A034386:= func< n | n eq 0 select 1 else LCM(PrimesInInterval(1, n)) >; A117692:= func< n, k | A034386(n)^2/(A034386(k)*A034386(n-k)) >; [(&+[A117692(n, k): k in [1..n]]): n in [1..40]]; // G. C. Greubel, Jul 23 2023 (SageMath) def A034386(n): return sloane.A002110(prime_pi(n)) def A117692(n, k): return A034386(n)^2/(A034386(k)*A034386(n-k)) def A117693(n): return sum(A117692(n, k) for k in range(1, n+1)) [A117693(n) for n in range(1, 41)] # G. C. Greubel, Jul 23 2023 CROSSREFS Cf. A034386, A117692. Sequence in context: A249135 A250387 A306429 * A153243 A186885 A097253 Adjacent sequences: A117690 A117691 A117692 * A117694 A117695 A117696 KEYWORD nonn,easy AUTHOR Roger L. Bagula, Apr 12 2006 EXTENSIONS Description simplified, offset corrected by the Assoc. Eds. of the OEIS, Jun 27 2010 STATUS approved

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Last modified August 7 22:54 EDT 2024. Contains 375018 sequences. (Running on oeis4.)