%I #7 May 28 2024 08:13:54
%S 1,2,3,4,5,6,7,8,9,10,1,11,2,12,3,13,4,14,5,15,6,16,7,17,8,18,9,19,10,
%T 20,1,11,21,2,12,22,3,13,23,4,14,24,5,15,25,6,16,26,7,17,27,8,18,28,9,
%U 19,29,10,20,30,1,11,21,31,2,12,22,32,3,13,23,33,4,14,24,34,5,15,25,35,6,16,26,36,7,17,27,37
%N Signature sequence of Pi^2.
%C Signature sequence of x = A002388: defined by sorting the values of i+j*x, i,j>=1, and collecting the list of the i in that order.
%H <a href="/index/Si#signature_sequences">Index entries for sequences related to signature sequences</a>
%p SIGSEQsort := proc(l1::list,l2::list)
%p if op(1,l1) < op(1,l2) then
%p return true ;
%p else
%p return false ;
%p end if
%p end proc:
%p SIGSEQ := proc(x,vmax)
%p local TBsrtd,i,j ;
%p TBsrtd := [] ;
%p for i from 1 do
%p if i > vmax then
%p break ;
%p end if;
%p for j from 1 do
%p if evalf(i+j*x) > vmax then
%p break ;
%p end if;
%p TBsrtd := [op(TBsrtd),[evalf(i+j*x),i]] ;
%p end do:
%p end do:
%p sort(TBsrtd,SIGSEQsort) ;
%p [seq(op(2,v),v=%)] ;
%p end proc:
%p Digits := 100 ;
%p SIGSEQ(Pi^2,150.0) ;
%Y Cf. A002388.
%K nonn
%O 1,2
%A _R. J. Mathar_, May 28 2024