A001209 -id:A001209 - cp's OEIS frontend

A005343 a(n) = solution to the postage stamp problem with n denominations and 8 stamps.

8, 28, 89, 234, 512, 1045, 2001, 3485

Offset: 1

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

R. K. Guy, Unsolved Problems in Number Theory, C12.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.
M. F. Challis and J. P. Robinson, Some Extremal Postage Stamp Bases, J. Integer Seq., 13 (2010), Article 10.2.3. [From John P Robinson (john-robinson(AT)uiowa.edu), Feb 18 2010]
Erich Friedman, Postage stamp problem
R. L. Graham and N. J. A. Sloane, On Additive Bases and Harmonious Graphs
R. L. Graham and N. J. A. Sloane, On Additive Bases and Harmonious Graphs, SIAM J. Algebraic and Discrete Methods, 1 (1980), 382-404.
W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.

Postage stamp sequences: A001208, A001209, A001210, A001211, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A014616, A053346, A053348, A075060, A084192, A084193.

Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004

a(8) from Challis and Robinson. John P Robinson (john-robinson(AT)uiowa.edu), Feb 18 2010

A005344 a(n) = solution to the postage stamp problem with n denominations and 9 stamps.

Original entry on oeis.org

9, 34, 112, 326, 797, 1617, 3191

Offset: 1

N. J. A. Sloane

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

R. K. Guy, Unsolved Problems in Number Theory, C12.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.
Erich Friedman, Postage stamp problem
R. L. Graham and N. J. A. Sloane, On Additive Bases and Harmonious Graphs
R. L. Graham and N. J. A. Sloane, On Additive Bases and Harmonious Graphs, SIAM J. Algebraic and Discrete Methods, 1 (1980), 382-404.
W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.

Postage stamp sequences: A001208, A001209, A001210, A001211, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A014616, A053346, A053348, A075060, A084192, A084193.

Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004

a(7) from Challis and Robinson by Robert Price, Jul 19 2013

A053346 a(n) = solution to the postage stamp problem with 7 denominations and n stamps.

Original entry on oeis.org

7, 26, 70, 162, 336, 638, 1137, 2001, 3191, 5047, 7820, 11568, 17178

Offset: 1

N. J. A. Sloane, Jun 20 2003

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

R. K. Guy, Unsolved Problems in Number Theory, C12.

R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.
M. F. Challis, Two new techniques for computing extremal h-bases A_kComp. J. 36(2) (1993) 117-126
M. F. Challis, J. P. Robinson, Some extremal postage stamp bases, JIS 13 (2010) #10.2.3.
Erich Friedman, Postage stamp problem
W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.
Eric Weisstein's World of Mathematics, Postage stamp problem

Postage stamp sequences: A001208, A001209, A001210, A001211, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A014616, A053346, A053348, A075060, A084192, A084193.

a(9) from Challis by R. J. Mathar, Apr 01 2006
Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004
a(10)-a(13) from Challis and Robinson by Robert Price, Jul 19 2013

A053348 a(n) = solution to the postage stamp problem with 8 denominations and n stamps.

Original entry on oeis.org

8, 32, 93, 228, 524, 1007, 1911, 3485

Offset: 1

N. J. A. Sloane, Jun 20 2003

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

R. K. Guy, Unsolved Problems in Number Theory, C12.

R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.
M. F. Challis, Two new techniques for computing extremal h-bases A_kComp. J. 36(2) (1993) 117-126
M. F. Challis, J. P. Robinson, Some extremal postage stamp bases, JIS 13 (2010) #10.2.3.
Erich Friedman, Postage stamp problem
W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.
Eric Weisstein's World of Mathematics, Postage stamp problem

Postage stamp sequences: A001208, A001209, A001210, A001211, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A014616, A053346, A053348, A075060, A084192, A084193.

a(6) from Challis by R. J. Mathar, Apr 01 2006
Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004
a(7)-a(8) from Challis and Robinson by Robert Price, Jul 19 2013

A075060 a(n) = solution to the postage stamp problem with n denominations and 10 stamps.

Original entry on oeis.org

10, 40, 146, 427, 1055, 2510, 5047

Offset: 1

N. J. A. Sloane, Jun 20 2003

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

R. K. Guy, Unsolved Problems in Number Theory, C12.

R. Alter and J. A. Barnett, A postage stamp problem, Amer. Math. Monthly, 87 (1980), 206-210.
M. F. Challis and J. P. Robinson, Some Extremal Postage Stamp Bases, J. Integer Seq., 13 (2010), Article 10.2.3. [From John P Robinson (john-robinson(AT)uiowa.edu), Feb 18 2010]
Erich Friedman, Postage stamp problem
W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.
Eric Weisstein's World of Mathematics, Postage stamp problem

Postage stamp sequences: A001208, A001209, A001210, A001211, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A014616, A053346, A053348, A075060, A084192, A084193.

Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004

a(7) from Challis and Robinson by John P Robinson (john-robinson(AT)uiowa.edu), Feb 18 2010

A084192 Array read by antidiagonals: T(n,k) = solution to postage stamp problem with n stamps and k denominations (n >= 1, k >= 1).

Original entry on oeis.org

1, 2, 2, 3, 4, 3, 4, 8, 7, 4, 5, 12, 15, 10, 5, 6, 16, 24, 26, 14, 6, 7, 20, 36, 44, 35, 18, 7, 8, 26, 52, 70, 71, 52, 23, 8, 9, 32, 70, 108, 126, 114, 69, 28, 9, 10, 40, 93, 162, 211, 216, 165, 89, 34, 10, 11, 46, 121, 228, 336, 388, 345, 234, 112, 40, 11, 12, 54, 154, 310, 524

Offset: 0

N. J. A. Sloane, Jun 20 2003

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given in this sequence and in A001208, A001209, A001210, A001211, A001212, ... are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

			Array begins:
   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11, ...
   2,   4,   7,  10,  14,  18,  23,  28,  34,  40, ...
   3,   8,  15,  26,  35,  52,  69,  89, 112, ...
   4,  12,  24,  44,  71, 114, 165, 234, ...
   5,  16,  36,  70, 126, 216, 345, ...
   6,  20,  52, 108, 211, 388, ...
   7,  26,  70, 162, 336, ...
   8,  32,  93, 228, ...
   9,  40, 121, ...
  10,  46, ...
  11, ...
  ...

Postage stamp sequences: A001208 A001209 A001210 A001211 A001212 A001213 A001214 A001215 A001216 A005342 A005343 A005344 A014616 A053346 A053348 A075060 A084192 A084193

A084193 gives transposed array. Rows and columns give rise to A014616, A001208, A001209, A001210, A001211, A053346, A053348, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A075060.

Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004
More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Jun 26 2003
Comments corrected by Shawn Pedersen, Apr 17 2012

A084193 Array read by antidiagonals: T(k,n) = solution to postage stamp problem with n stamps and k denominations (n >= 1, k >= 1).

Original entry on oeis.org

1, 2, 2, 3, 4, 3, 4, 7, 8, 4, 5, 10, 15, 12, 5, 6, 14, 26, 24, 16, 6, 7, 18, 35, 44, 36, 20, 7, 8, 23, 52, 71, 70, 52, 26, 8, 9, 28, 69, 114, 126, 108, 70, 32, 9, 10, 34, 89, 165, 216, 211, 162, 93, 40, 10, 11, 40, 112, 234, 345, 388, 336, 228, 121, 46, 11, 12, 47, 146, 326, 512

Offset: 0

N. J. A. Sloane, Jun 20 2003

Fred Lunnon [W. F. Lunnon] defines "solution" to be the smallest value not obtainable by the best set of stamps. The solutions given in this sequence and in A001208, A001209, A001210, A001211, A001212, ... are one lower than this, that is, the sequence gives the largest number obtainable without a break using the best set of stamps.

			Array begins:
   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11, ...
   2,   4,   8,  12,  16,  20,  26,  32,  40,  46, ...
   3,   7,  15,  24,  36,  52,  70,  93, 121, ...
   4,  10,  26,  44,  70, 108, 162, 228, ...
   5,  14,  35,  71, 126, 211, 336, ...
   6,  18,  52, 114, 216, 388, ...
   7,  23,  69, 165, 345, ...
   8,  28,  89, 234, ...
   9,  34, 112, ...
  10,  40, ...
  11, ...
  ...

Index to sequences related to the Postage Stamp Problem

A084192 gives transposed array. Rows and columns give rise to A014616, A001208, A001209, A001210, A001211, A053346, A053348, A001212, A001213, A001214, A001215, A001216, A005342, A005343, A005344, A075060.

Entry improved by comments from John Seldon (johnseldon(AT)onetel.com), Sep 15 2004
More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Jun 26 2003
Comments corrected by Shawn Pedersen, Apr 17 2012

A196416 Table read by antidiagonals: V(n,m) = solution to postage stamp problem with n stamps in set, m stamps on letter.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 5, 4, 1, 1, 5, 8, 9, 5, 1, 1, 6, 11, 16, 13, 6, 1, 1, 7, 15, 27, 25, 17, 7, 1, 1, 8, 19, 36, 45, 37, 21, 8, 1, 1, 9, 24, 53, 72, 71, 53, 27, 9, 1, 1, 10, 29, 70, 115, 127, 109, 71, 33, 10, 1

Offset: 0

N. J. A. Sloane, Oct 01 2011

Given n, m, the postage stamp problem is to choose a set of n nonnegative integers such that the sums of m or fewer of these integers can realize the numbers 1, 2, ..., N-1, where N is as large as possible. V(n,m) denotes the value of N.

			Array begins:
m\n 0 1 2 3 4 5 6 ...
---------------------
0...1 1 1 1 1 1 1 ...
1...1 2 3 4 5 6 7  ...
2...1 3 5 9 13 17 21  ...
3...1 4 8 16 25 37 53 ...
4...1 5 11 27 45 71 109  ...
5...1 6 15 36 72 127 212  ...
6...1 7 19 53 115 217 389  ...
...

W. F. Lunnon, A postage stamp problem, Comput. J. 12 (1969) 377-380.

Rows and columns include: A014616/A024206, A195618/A001208, A196069/A001209, A001210, A001211, A196094/A001212, A001213, A001214, A001215, A001216.

A002437 a(n) = A000364(n) * (3^(2*n+1) + 1)/4.

Original entry on oeis.org

1, 7, 305, 33367, 6815585, 2237423527, 1077270776465, 715153093789687, 626055764653322945, 698774745485355051847, 968553361387420436695025, 1632180870878422847476890007, 3286322019402928956112227932705, 7791592461957309952817483706344167, 21485762937086358457367440231243675985

Offset: 0

N. J. A. Sloane

The terms are multiples of the Euler numbers (A000364).

			a(4) = A000364(4) * (3^(2*4+1)+1)/4 = 1385 * (3^9+1)/4 = 1385 * 4921 = 6815585.

A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 75.
J. W. L. Glaisher, Messenger of Math., 28 (1898), 36-79, see esp. p. 51.
L. B. W. Jolley, Summation of Series, Dover, 2nd ed. (1961)
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Vincenzo Librandi, Table of n, a(n) for n = 0..200
Michael E. Hoffman, Derivative Polynomials, Euler Polynomials, and Associated Integer Sequences, The Electronic Journal of Combinatorics, vol. 6, no. 1, #R21, (1999).

Bisections: A156168, A156169.
Cf. A000191, A001209, A012494, A000364, A000281, A156134, A349429.
Cf. other sequences with a g.f. of the form cos(x)/(1 - k*sin^2(x)): A012494 (k=-1),  A001209 (k=1/2), A000364 (k=1), A000281 (k=2), A156134 (k=3).

Q:=proc(n) option remember; if n=0 then RETURN(1); else RETURN(expand((u^2+1)*diff(Q(n-1),u)+u*Q(n-1))); fi; end;
[seq(subs(u=sqrt(3),Q(2*n)),n=0..25)];

Table[Abs[EulerE[2 n]] (3^(2 n + 1) + 1) / 4, {n, 0, 30}] (* Vincenzo Librandi, Feb 07 2017 *)

A000364(n) * (3^(2*n+1) + 1)/4.
Q_2n(sqrt(3)), where the polynomials Q_n() are defined in A104035. - N. J. A. Sloane, Nov 06 2009
a(n) = (-1)^n*Sum_{k = 0..2*n-1} w^(2*n+k)*Sum_{j = 1..2*n-1} (-1)^(k-j)*binomial(2*n-1,k-j)*(2*j - 1)^(2*n-2), where  w = exp(2*Pi*i/6) (i = sqrt(-1)). Cf. A002439. - Peter Bala, Jan 21 2011
Sum_{n>=1} (-1)^floor((n-1)/2) 1/A007310(n)^s = r_s with r_{2s+1} = 2 *(Pi/6)^(2s+1) *a(s) /(2s)!. [Jolley eq (315)]. - R. J. Mathar, Mar 24 2011
From Peter Bala, Feb 06 2017: (Start)
E.g.f.: cos(x)^2/cos(3*x) = cos(x)/(1 - 4*sin(x)^2) = 1 + 7*x^2/2! + 305*x^4/4! + 33367*x^6/6! + .... This is the even part of (1/2)*sec(x + Pi/3). Cf. A000191. (End)
a(n) = (1/2)*Integral_{x = 0..inf} x^(2*n)*cosh(Pi*x/3)/cosh(Pi*x/2) dx. - Cf. A000281. - Peter Bala, Nov 08 2019

More terms from Herman P. Robinson

Further terms from N. J. A. Sloane, Nov 06 2009

A012494 Expansion of e.g.f. arctan(sin(x)) (odd powers only).

Original entry on oeis.org

1, -3, 45, -1743, 125625, -14554683, 2473184805, -579439207623, 179018972217585, -70518070842040563, 34495620120141463965, -20515677772241956573503, 14578232896601243652363945, -12198268199871431840616166443, 11871344562637111570703016357525

Offset: 0

Patrick Demichel (patrick.demichel(AT)hp.com)

arctan(sin(x)) = x - 3*x^3/3! + 45*x^5/5! - 1743*x^7/7! + 125625*x^9/9! + ....
Absolute values are coefficients in expansion of
arctanh(arcsinh(x)) = x + 3*x^3/3! + 45*x^5/5! + 1743*x^7/7! + ....
arccot(sin(x)) = Pi/2 - x + 3*x^3/3! - 45*x^5/5! + 1743*x^7/7! - ....

Vincenzo Librandi, Table of n, a(n) for n = 0..127

Bisection of A003704, A013208.
Cf. A101923, A001209, A000364, A000281, A156134, A002437.
Cf. other sequences with a g.f. of the form cos(x)/(1 - k*sin^2(x)): A000364 (k=1), A001209 (k=1/2), A000281 (k=2), A156134 (k=3), A002437 (k=4).

a:= n-> (t-> t!*coeff(series(arctan(sin(x)), x, t+1), x, t))(2*n+1):
seq(a(n), n=0..20);  # Alois P. Heinz, Aug 16 2018

Drop[ Range[0, 25]! CoefficientList[ Series[ ArcTan[ Sin[x]], {x, 0, 25}], x], {1, 25, 2}] (* Or *)
f[n_] := n!Sum[(1 + (-1)^(n - 2k + 1))2^(1 - 2k)Sum[(-1)^((n + 1)/2 - j)Binomial[2k - 1, j]((2j - 2k + 1)^n/n!)/(2k - 1), {j, 0, (2k - 1)/2}], {k, Ceiling[n/2]}]; Table[ f[n], {n, 1, 25, 2}] (* Robert G. Wilson v *)

a(n):=n!*sum((1+(-1)^(n-2*k+1))*2^(1-2*k)*sum((-1)^((n+1)/2-i)*binomial(2*k-1,i)*(2*i-2*k+1)^n/n!,i,0,(2*k-1)/2)/(2*k-1),k,1,ceiling((n)/2)); /* Vladimir Kruchinin, Feb 25 2011 */

a(n):=sum(sum((2*i-2*k-1)^(2*n+1)*binomial(2*k+1,i)*(-1)^(n-i+1),i,0,k)/(4^k*(2*k+1)),k,0,n); /* Vladimir Kruchinin, Feb 04 2012 */

a(n) = n!*sum(k=1..ceiling(n/2), (1+(-1)^(n-2*k+1))*2^(1-2*k)*sum(i=0..(2*k-1)/2, (-1)^((n+1)/2-i)*binomial(2*k-1,i)*(2*i-2*k+1)^n/n!)/(2*k-1)), n>0. Vladimir Kruchinin, Feb 25 2011
G.f.: cos(x) /(1 + sin^2(x)) = 1 - 3*x^2/2! + 45*x^4/4! - ... . - Peter Bala, Feb 06 2017
a(n) ~ (-1)^n * (2*n)! / (log(1+sqrt(2)))^(2*n+1). - Vaclav Kotesovec, Aug 17 2018

cp's OEIS Frontend

A005343 a(n) = solution to the postage stamp problem with n denominations and 8 stamps.

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A005344 a(n) = solution to the postage stamp problem with n denominations and 9 stamps.

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A053346 a(n) = solution to the postage stamp problem with 7 denominations and n stamps.

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A053348 a(n) = solution to the postage stamp problem with 8 denominations and n stamps.

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A075060 a(n) = solution to the postage stamp problem with n denominations and 10 stamps.

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A084192 Array read by antidiagonals: T(n,k) = solution to postage stamp problem with n stamps and k denominations (n >= 1, k >= 1).

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A084193 Array read by antidiagonals: T(k,n) = solution to postage stamp problem with n stamps and k denominations (n >= 1, k >= 1).

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A196416 Table read by antidiagonals: V(n,m) = solution to postage stamp problem with n stamps in set, m stamps on letter.

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A002437 a(n) = A000364(n) * (3^(2*n+1) + 1)/4.

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