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A090622 Square array read by antidiagonals of highest power of k dividing n! (with n,k>1). 18

%I #22 Jan 19 2017 16:27:54

%S 1,0,1,0,1,3,0,0,1,3,0,0,1,1,4,0,1,0,1,2,4,0,0,1,1,2,2,7,0,0,0,1,1,2,

%T 2,7,0,0,1,0,2,1,3,4,8,0,0,0,1,0,2,1,3,4,8,0,0,0,0,1,1,2,1,4,4,10,0,0,

%U 0,1,1,1,1,4,2,4,5,10,0,0,1,0,1,1,2,1,4,2,5,5,11,0,0,0,1,0,1,1,2,1,4,2,5,5,11

%N Square array read by antidiagonals of highest power of k dividing n! (with n,k>1).

%H Alois P. Heinz, <a href="/A090622/b090622.txt">Antidiagonals n = 2..142, flattened</a>

%F For k=p prime: T(n,p) = [n/p] + [n/p^2] + [n/p^3] + .... For k = p^m a prime power: T(n,p^m) = [T(n,p)/m]. For k = b*c with b and c coprime: T(n,a*b) = min(T(n,a), T(n,b)). T(n,k) is close to, but below, n/A090624(k).

%e Square array starts:

%e 1, 0, 0, 0, 0, 0, 0, ...

%e 1, 1, 0, 0, 1, 0, 0, ...

%e 3, 1, 1, 0, 1, 0, 1, ...

%e 3, 1, 1, 1, 1, 0, 1, ...

%e 4, 2, 2, 1, 2, 0, 1, ...

%e 4, 2, 2, 1, 2, 1, 1, ...

%e 7, 2, 3, 1, 2, 1, 2, ...

%p f:= proc(n, p) local c, k; c, k:= 0, p;

%p while n>=k do c:= c+iquo(n, k); k:= k*p od; c

%p end:

%p T:= (n, k)-> min(seq(iquo(f(n, i[1]), i[2]), i=ifactors(k)[2])):

%p seq(seq(T(n, 2+d-n), n=2..d), d=2..20); # _Alois P. Heinz_, Oct 04 2012

%t f[n_, p_] := Module[{c = 0, k = p}, While[n >= k , c = c + Quotient[n, k]; k = k*p ]; c ]; t[n_, k_] := Min[ Table[ Quotient[f[n, i[[1]]], i[[2]]], {i, FactorInteger[k]}]]; Table[ Table[t[n, 2 + d - n], {n, 2, d}], {d, 2, 20}] // Flatten (* _Jean-François Alcover_, Oct 03 2013, translated from Alois P. Heinz's Maple program *)

%Y Columns include A011371, A054861, A090616, A027868, A054861, A054896, A090617, A090618, A027868, A064458, A090619, A090620, A054896, A027868, A090621.

%Y Cf. A090623, A090624, A115627.

%Y Diagonal gives A011776. - _Alois P. Heinz_, Oct 04 2012

%K nonn,tabl

%O 2,6

%A _Henry Bottomley_, Dec 06 2003

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Last modified March 29 03:41 EDT 2024. Contains 371264 sequences. (Running on oeis4.)