A007442
Inverse binomial transform of primes.
Original entry on oeis.org
2, 1, 1, -1, 3, -9, 23, -53, 115, -237, 457, -801, 1213, -1389, 445, 3667, -15081, 41335, -95059, 195769, -370803, 652463, -1063359, 1570205, -1961755, 1560269, 1401991, -11023119, 36000427, -93408425, 214275735, -450374071, 879254493, -1599245737, 2695465017
Offset: 1
a(4) = 7 - 3*5 + 3*3 - 2 = -1.
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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Diff[lst_List] := Table[lst[[i + 1]] - lst[[i]], {i, Length[lst] - 1}]; n=1000; dt = Prime[Range[n]]; a = Range[n]; a[[1]] = 2; Do[dt = Diff[dt]; a[[i]] = dt[[1]], {i, 2, n}]; a
u = Table[Prime[Range[k]], {k, 1, 100}];Flatten[Table[Differences[u[[k]], k - 1], {k, 1, 100}]] (* Clark Kimberling, May 15 2015 *)
t = Array[Prime, 30]; f[x_] := Rest[x] - Most[x];
Flatten[Last /@ (NestList[f, t[[1 ;; #]], (# - 1)] & /@ Range[1, 29])] (* Horst H. Manninger, Mar 22 2021 *)
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vector(50, n, sum(k=0, n-1,(-1)^(n-k-1)*binomial(n-1, k)*prime(k+1))) \\ Altug Alkan, Oct 17 2015
Incorrect conjecture concerning the sign of even terms removed by
Glen Whitney, Nov 10 2024
A140119
Extrapolation for (n + 1)-st prime made by fitting least-degree polynomial to first n primes.
Original entry on oeis.org
2, 4, 8, 8, 22, -6, 72, -92, 266, -426, 838, -1172, 1432, -398, -3614, 15140, -41274, 95126, -195698, 370876, -652384, 1063442, -1570116, 1961852, -1560168, -1401888, 11023226, -36000318, 93408538, -214275608, 450374202, -879254356, 1599245876, -2695464868, 4138070460, -5539280974
Offset: 1
Jonathan Wellons (wellons(AT)gmail.com), May 08 2008
The lowest-order polynomial having points (1,2), (2,3), (3,5) and (4,7) is f(x) = 1/6 (-x^3 +9x^2 -14x +18). When evaluated at x = 5, f(5) = 8.
A082674
Constant term when a polynomial of degree n is fitted to the lower members of the first n+1 twin prime pairs.
Original entry on oeis.org
1, 5, 9, 19, 41, 87, 187, 425, 1041, 2689, 7031, 18015, 44503, 105503, 240267, 527035, 1116023, 2283321, 4509661, 8574251, 15613035, 26989459, 43596473, 63714861, 77517775, 54160583, -87072621, -539390369, -1742001769, -4661299497
Offset: 1
A 5th-degree polynomial through the 6 points (1, 3), (2, 5), (3, 11), (4, 17), (5, 29), (6, 41) has constant term 41.
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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
A082675
Constant term when a polynomial of degree <= n is fitted to the first n+1 upper members of the twin prime pairs.
Original entry on oeis.org
3, 7, 11, 21, 43, 89, 189, 427, 1043, 2691, 7033, 18017, 44505, 105505, 240269, 527037, 1116025, 2283323, 4509663, 8574253, 15613037, 26989461, 43596475, 63714863, 77517777, 54160585, -87072619, -539390367, -1742001767, -4661299495
Offset: 1
A 5th degree polynomial through the 6 points (1, 5), (2, 7), (3, 13), (4, 19), (5, 31), (6, 43) has constant term 43.
Equals lower-member sequence (
A082674) + 2.
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A006512 := 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+1) ) ; fi ; i := i+1 ; od ; end: A082675 := 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] := A006512(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,",A082675(n)) ; od ; # R. J. Mathar, Oct 31 2006
A293210
a(n) = [x^n] (1/(1 - x)^n)*Sum_{k>=1} prime(k)*x^k.
Original entry on oeis.org
0, 2, 7, 26, 97, 366, 1388, 5288, 20225, 77618, 298766, 1153018, 4460072, 17287558, 67129566, 261095420, 1016994627, 3966529870, 15488964428, 60549061804, 236932924494, 927984726826, 3637661249946, 14270586372348, 56024073085546, 220089137078792, 865154426179408, 3402841810234762, 13391422390407194
Offset: 0
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Table[SeriesCoefficient[1/(1 - x)^n Sum[Prime[k] x^k, {k, 1, n}], {x, 0, n}], {n, 0, 28}]
Showing 1-5 of 5 results.
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