This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A376684 #11 Oct 17 2024 08:23:34
%S A376684 1,3,4,9,12,27,50,109,224,471,942,1773,3118,4957,7038,9373,16256,
%T A376684 55461,150622,346763,718972,1377101,2462220,4114987,6387718,9112455,
%U A376684 12051830,17160117,40946860,134463917,349105370,800713921,1684145408,3297536923,6040907554
%N A376684 Antidiagonal-sums of the absolute value of the array A376682(n,k) = n-th term of the k-th differences of the noncomposite numbers (A008578).
%e A376684 The fourth antidiagonal of A376682 is: (7, 2, 0, -1, -2), so a(4) = 12.
%t A376684 nn=12;
%t A376684 t=Table[Take[Differences[NestList[NestWhile[#+1&,#+1,!PrimeQ[#]&]&,1,2*nn],k],nn],{k,0,nn}];
%t A376684 Total/@Table[Abs[t[[j,i-j+1]]],{i,nn},{j,i}]
%Y A376684 For the modern primes (A000040) we have A376681, absolute version of A140119.
%Y A376684 For firsts instead of row-sums we have A030016, modern A007442.
%Y A376684 These are the antidiagonal-sums of the absolute value of A376682 (modern A095195).
%Y A376684 This is the absolute version of A376683.
%Y A376684 For first zero-positions we have A376855, modern A376678.
%Y A376684 A000040 lists the modern primes, differences A001223, seconds A036263.
%Y A376684 A008578 lists the noncomposites, first differences A075526.
%Y A376684 Cf. A002808, A064113, A065890, A173390, A233671, A258025, A333214, A333254, A376680, A377033, A377037.
%K A376684 nonn
%O A376684 0,2
%A A376684 _Gus Wiseman_, Oct 15 2024