cp's OEIS Frontend

A343043 a(n) = A343042(n, n).

%I A343043 #12 Apr 08 2021 00:34:00
%S A343043 0,1,6,9,12,15,120,127,150,153,156,159,240,247,270,273,300,303,360,
%T A343043 367,390,393,420,423,5040,5065,5166,5193,5172,5199,5880,5911,5910,
%U A343043 5913,5916,5919,6000,6031,6030,6033,6060,6063,6120,6151,6150,6153,6180,6183,10080
%N A343043 a(n) = A343042(n, n).
%C A343043 This sequence has similarities with A087019 and A343047.
%H A343043 Rémy Sigrist, <a href="/A343043/b343043.txt">Table of n, a(n) for n = 0..5039</a>
%H A343043 Rémy Sigrist, <a href="/A343043/a343043.gp.txt">PARI program for A343043</a>
%H A343043 <a href="/index/Di#dismal">Index entries for sequences related to dismal (or lunar) arithmetic</a>
%H A343043 <a href="/index/Fa#facbase">Index entries for sequences related to factorial base representation</a>
%F A343043 a(k!) = (2*k-1)! for any k > 0.
%F A343043 a(A007489(k)) = A007489(2*k-1) for any k > 0.
%e A343043 For n = 42:
%e A343043 - the factorial base representation of 42 is "1300", so:
%e A343043               1 3 0 0
%e A343043             x 1 3 0 0
%e A343043             ---------
%e A343043               0 0 0 0
%e A343043             0 0 0 0
%e A343043           1 3 0 0
%e A343043       + 1 1 0 0
%e A343043       ---------------
%e A343043         1 1 3 0 0 0 0
%e A343043 - hence a(42) = 7! + 6! + 3*5! = 6120.
%o A343043 (PARI) See Links section.
%Y A343043 Cf. A007489, A087019, A343042, A343047.
%K A343043 nonn,base
%O A343043 0,3
%A A343043 _Rémy Sigrist_, Apr 05 2021