login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Sum of the absolute values in row n of A118686.
2

%I #15 Mar 31 2024 08:45:34

%S 1,2,4,12,84,588,18228,565068,119229348,25157392428,5308209802308,

%T 1120032268286988,2588394572011229268,5981779855917950838348,

%U 179638830853071981626428788,5394733729348604680223282932428,162009248626067947151785409743745268

%N Sum of the absolute values in row n of A118686.

%H G. C. Greubel, <a href="/A119489/b119489.txt">Table of n, a(n) for n = 0..75</a>

%F a(n) = Sum_{k=0..n} abs( A118686(n,k) ).

%t g[n_]:= If[PrimeQ[n], n, 1]; p[n_]:= p[n]= If[n==0,1,g[n]*p[n-1]];

%t A119489= Flatten[Join[{{1}}, Table[Apply[Plus, Abs[Reverse[ CoefficientList[Product[x-p[n], {n,0,m}], x]]]], {m,0,30}]]]

%o (Magma)

%o R<x>:=PowerSeriesRing(Rationals(), 50);

%o g:= func< n | IsPrime(n) select n else 1 >;

%o p:=[1] cat [n le 1 select 1 else g(n)*Self(n-1): n in [1..50]];

%o T:= func< n,k | k eq 0 select 1 else Coefficient(R!( (&*[x-p[j+1]: j in [0..n-1]]) ), n-k) >;

%o [(&+[Abs(T(n,k)): k in [0..n]]): n in [0..30]]; // _G. C. Greubel_, Mar 31 2024

%o (SageMath)

%o def g(n): return n if is_prime(n) else 1

%o def p(n): return 1 if n==0 else g(n)*p(n-1)

%o def T(n,k): return 1 if k==0 else ( product(x-p(j) for j in range(n)) ).series(x, n+2).list()[n-k] # T = A118686

%o [sum(abs(T(n,k)) for k in range(n+1)) for n in range(31)] # _G. C. Greubel_, Mar 31 2024

%Y Cf. A118686.

%K nonn

%O 0,2

%A _Roger L. Bagula_, May 25 2006

%E Terms a(12) onward added by _G. C. Greubel_, Mar 31 2024