cp's OEIS Frontend

A278492 Square array where row n (n >= 0) gives the numbers remaining after the n-th round of the Flavius sieve, read by descending antidiagonals.

%I A278492 #23 Dec 23 2024 14:53:44
%S A278492 1,2,1,3,3,1,4,5,3,1,5,7,7,3,1,6,9,9,7,3,1,7,11,13,13,7,3,1,8,13,15,
%T A278492 15,13,7,3,1,9,15,19,19,19,13,7,3,1,10,17,21,25,25,19,13,7,3,1,11,19,
%U A278492 25,27,27,27,19,13,7,3,1,12,21,27,31,31,31,27,19,13,7,3,1,13,23,31,37,39,39,39,27,19,13,7,3,1
%N A278492 Square array where row n (n >= 0) gives the numbers remaining after the n-th round of the Flavius sieve, read by descending antidiagonals.
%C A278492 The terms of square array A(row,col) are read by descending antidiagonals as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...
%H A278492 Antti Karttunen, <a href="/A278492/b278492.txt">Table of n, a(n) for n = 0..10439; the first 144 antidiagonals of the array</a>
%H A278492 D. Wilson et al., <a href="https://web.archive.org/web/*/http://list.seqfan.eu/oldermail/seqfan/2016-November/thread.html">Interesting sequence</a>, SeqFan list, Nov. 2016
%H A278492 <a href="/index/Si#sieve">Index entries for sequences generated by sieves</a>
%H A278492 <a href="/index/J#Josephus">Index entries for sequences related to the Josephus Problem</a>
%F A278492 A(n,k) = 1 + A278482(n,k).
%e A278492 The top left corner of the array:
%e A278492 1, 2, 3,  4,  5,  6,  7,  8,  9, 10 (row 0: start from A000027)
%e A278492 1, 3, 5,  7,  9, 11, 13, 15, 17, 19 (after the 1st round, A005408 remain)
%e A278492 1, 3, 7,  9, 13, 15, 19, 21, 25, 27 (after the 2nd, A047241)
%e A278492 1, 3, 7, 13, 15, 19, 25, 27, 31, 37
%e A278492 1, 3, 7, 13, 19, 25, 27, 31, 39, 43
%e A278492 1, 3, 7, 13, 19, 27, 31, 39, 43, 49
%e A278492 1, 3, 7, 13, 19, 27, 39, 43, 49, 61
%e A278492 1, 3, 7, 13, 19, 27, 39, 49, 61, 63
%e A278492 1, 3, 7, 13, 19, 27, 39, 49, 63, 67
%e A278492 1, 3, 7, 13, 19, 27, 39, 49, 63, 79
%o A278492 (Scheme)
%o A278492 (define (A278492 n) (A278492bi (A002262 n) (A025581 n)))
%o A278492 (define (A278492bi row col) (+ 1 (A278482bi row col)))
%Y A278492 One more than A278482.
%Y A278492 Transpose: A278493.
%Y A278492 Rows: A000027, A005408, A047241, A056530, A056531.
%Y A278492 Main diagonal: A000960.
%Y A278492 Cf. A278507 (the numbers removed at each round).
%Y A278492 Similarly constructed arrays for other sieves: A258207, A260717.
%K A278492 nonn,tabl
%O A278492 0,2
%A A278492 _Antti Karttunen_, Nov 23 2016, after _David W. Wilson_'s posting on SeqFan-list Nov 22 2016