login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Constant term when a polynomial of degree n is fitted to the lower members of the first n+1 twin prime pairs.
2

%I #25 Apr 05 2024 12:39:32

%S 1,5,9,19,41,87,187,425,1041,2689,7031,18015,44503,105503,240267,

%T 527035,1116023,2283321,4509661,8574251,15613035,26989459,43596473,

%U 63714861,77517775,54160583,-87072621,-539390369,-1742001769,-4661299497

%N Constant term when a polynomial of degree n is fitted to the lower members of the first n+1 twin prime pairs.

%F a(n) = A082675(n) - 2.

%e A 5th-degree polynomial through the 6 points (1, 3), (2, 5), (3, 11), (4, 17), (5, 29), (6, 41) has constant term 41.

%p A088460 := proc(n) local i,p ; i := 1 ; p := 0 ; while true do while ithprime(i+1)-ithprime(i) <> 2 do i := i+1 ; od ; p := p+1 ; if p = n then RETURN( ithprime(i) ) ; fi ; i := i+1 ; od ; end: A082674 := proc(n) local rhs,co, row,col; rhs := linalg[vector](n+1) ; co := linalg[matrix](n+1,n+1) ; for row from 1 to n+1 do rhs[row] := A088460(row) ; for col from 1 to n+1 do co[row,col] := row^(col-1) ; od ; od ; linalg[linsolve](co,rhs)[1] ; end: for n from 1 to 30 do printf("%d,",A082674(n)) ; od ; # _R. J. Mathar_, Oct 31 2006

%Y Cf. A001359, A082594, A082675.

%K easy,sign

%O 1,2

%A _Cino Hilliard_, May 19 2003

%E Corrected and extended by _R. J. Mathar_, Oct 31 2006