cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 11 results. Next

A035382 Number of partitions of n into parts congruent to 1 mod 3.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 2, 3, 4, 4, 5, 6, 7, 8, 10, 11, 13, 15, 17, 19, 23, 26, 29, 33, 38, 42, 48, 54, 61, 68, 77, 85, 96, 107, 119, 132, 148, 163, 181, 201, 223, 245, 272, 299, 330, 363, 400, 438, 483, 529, 580, 635, 697, 760, 832, 908, 992, 1081, 1180, 1283, 1399, 1521
Offset: 0

Views

Author

Keywords

Comments

a(n) = A116373(3*n). - Reinhard Zumkeller, Feb 15 2006

Examples

			a(3) = 1 because we have [1,1,1];
a(4) = 2 because we have [1,1,1,1] and [4];
a(9) = 4 because we have [7,1,1], [4,4,1], [4,1,1,1,1,1] and [1,1,1,1,1,1,1,1,1].
1 + x + x^2 + x^3 + 2*x^4 + 2*x^5 + 2*x^6 + 3*x^7 + 4*x^8 + 4*x^9 + ...
		

Crossrefs

Programs

  • Maple
    g:= 1/product(1-x^(1+3*j), j=0..50): gser:= series(g, x=0, 64): seq(coeff(gser, x, n), n=0..61); # Emeric Deutsch, Mar 30 2006
    # second Maple program
    b:= proc(n, i) option remember; `if`(n=0, 1,
          `if`(i<1, 0, b(n, i-3) +`if`(i>n, 0, b(n-i, i))))
        end:
    a:= n-> b(n, 3*iquo(n, 3)+1):
    seq(a(n), n=0..100);  # Alois P. Heinz, Oct 03 2012
  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0, 1, If[i<1, 0, b[n, i-3] + If[i>n, 0, b[n-i, i]]]]; a[n_] := b[n, 3*Quotient[n, 3]+1]; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Mar 23 2015, after Alois P. Heinz *)
    nmax = 100; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = -1; Do[If[Mod[k, 3] == 1, Do[poly[[j + 1]] -= poly[[j - k + 1]], {j, nmax, k, -1}];], {k, 2, nmax}]; poly2 = Take[poly, {2, nmax + 1}]; poly3 = 1 + Sum[poly2[[n]]*x^n, {n, 1, Length[poly2]}]; CoefficientList[Series[1/poly3, {x, 0, Length[poly2]}], x] (* Vaclav Kotesovec, Jan 13 2017 *)
    nmax = 50; s = Range[0, nmax/3]*3 + 1;
    Table[Count[IntegerPartitions@n, x_ /; SubsetQ[s, x]], {n, 0, nmax}] (* Robert Price, Aug 05 2020 *)

Formula

a(n) = 1/n*Sum_{k=1..n} A078181(k)*a(n-k), a(0) = 1.
G.f.: 1/prod(j>=0, 1-x^(1+3*j) ). - Emeric Deutsch, Mar 30 2006
From Joerg Arndt, Oct 02 2012: (Start)
G.f.: sum(n>=0, q^n/prod(k=1..n, 1-q^(3*k)) ); this is the special case of R=1, M=3 of the g.f. sum(n>=0, q^(R*n)/prod(k=1..n, 1-q^(M*k) ) ) for partitions into parts R mod M (where R!=0).
G.f. sum(n>=0, q^(3*n^2-2*n) / prod(k=0..n-1, (1-q^(3*k+3))*(1-q^(3*k+1))) ); this is the special case of R=1, M=3 of the g.f. sum(n>=0, q^(M*n^2+(R-M)*n) / prod(k=0..n-1, (1-q^(M*k+M))*(1-q^(M*k+R))) ) for partitions into parts R mod M (where R!=0). (See Fxtbook link)
(End)
a(n) ~ Gamma(1/3) * exp(sqrt(2*n)*Pi/3) / (2*sqrt(3) * (2*Pi*n)^(2/3)) * (1 + (Pi/72 - 2/(3*Pi)) / sqrt(2*n)). - Vaclav Kotesovec, Feb 26 2015, extended Jan 24 2017
Euler transform of period 3 sequence [ 1, 0, 0, ...]. - Kevin T. Acres, Apr 28 2018

A114099 Number of partitions of n into parts with digital root = 9.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 22, 0, 0, 0, 0, 0, 0, 0, 0, 30, 0, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0, 0, 56, 0, 0, 0
Offset: 0

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n).

Examples

			a(27) = #{27, 18+9, 9+9+9} = 3.
		

Crossrefs

Programs

Formula

a(n) = A000041(floor(n/9))*0^(n mod 9).
a(9n) = A000041(n) and for all others a(n) = 0. [Robert G. Wilson v, Apr 25 2010]

A114102 Number of partitions of n such that all parts of a partition have the same digital root.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 3, 7, 4, 5, 7, 6, 5, 8, 5, 8, 11, 8, 7, 16, 9, 10, 13, 12, 10, 22, 11, 15, 23, 16, 16, 26, 16, 18, 32, 22, 21, 41, 24, 27, 40, 28, 26, 55, 30, 36, 59, 40, 38, 65, 41, 45, 77, 48, 51, 95, 57, 60, 97, 66, 63, 119, 68, 80, 131, 89, 85, 150, 91, 96, 166, 104
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A116371(n) + A116372(n) + A116373(n) + A116374(n) + A116375(n) + A116376(n) + A116377(n) + A116378(n) + A114099(n).

Examples

			a(10) = #{10, 5+5, 2+2+2+2+2, 10x1} = 4;
a(11) = #{11, 10+1, 11x1} = 3;
a(12) = #{12, 10+1+1, 6+6, 4+4+4, 3+3+3+3, 2+2+2+2+2+2, 12x1} = 7.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]
A156144. [From Reinhard Zumkeller, Feb 05 2009]

Programs

  • Haskell
    a114102 n = length $ filter (== 1) $
                map (length . nub . (map a010888)) $ ps 1 n
       where ps x 0 = [[]]
             ps x y = [t:ts | t <- [x..y], ts <- ps t (y - t)]
    -- Reinhard Zumkeller, Feb 04 2014

A116371 Number of partitions of n into parts with digital root = 1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7, 8, 10, 11, 12, 12, 12, 12, 12, 12, 13, 15, 17, 18, 19, 19, 19, 19, 19, 20, 23, 26, 28, 29, 30, 30, 30, 30, 31, 34, 38, 41, 43, 44, 45, 45, 45, 46, 50, 55, 60, 63, 65, 66, 67, 67, 68
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(18) = #{10+8x1, 18x1} = 2;
a(19) = #{19, 10+9x1, 19x1} = 3;
a(20) = #{19+1, 10+10, 10+10x1, 19x1} = 4.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]
A017173, A156144, A156145. [From Reinhard Zumkeller, Feb 05 2009]

Programs

  • Haskell
    a116371 n = p a017173_list n where
       p _  0 = 1
       p [] _ = 0
       p ks'@(k:ks) m = if m < k then 0 else p ks' (m - k) + p ks m
    -- Reinhard Zumkeller, Feb 04 2014

A116376 Number of partitions of n into parts with digital root = 6.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 1, 0, 0, 3, 0, 0, 2, 0, 0, 3, 0, 0, 3, 0, 0, 4, 0, 0, 4, 0, 0, 6, 0, 0, 5, 0, 0, 7, 0, 0, 7, 0, 0, 9, 0, 0, 9, 0, 0, 12, 0, 0, 11, 0, 0, 15, 0, 0, 15, 0, 0, 18, 0, 0, 19, 0, 0, 23, 0, 0, 23, 0, 0, 29, 0, 0, 29, 0, 0, 35, 0, 0, 37
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(30) = #{24+6, 15+15, 6+6+6+6+6} = 3.
		

Crossrefs

Cf. A010888.
Cf. A147706.

Programs

  • Maple
    N:= 1000: # to get a(1) to a(N)
    g:= mul(1/(1-x^(6+9*j)), j=0..floor((N-6)/9)):
    S:= series(g, x, N+1):
    seq(coeff(S,x,j),j=1..N); # Robert Israel, Apr 13 2015

Formula

a(n) = A035386(floor(n/3))*0^(n mod 3).
G.f.: Product_{j>=0} 1/(1 - x^(6+9*j)). - Robert Israel, Apr 13 2015

A116372 Number of partitions of n into parts with digital root = 2.

Original entry on oeis.org

0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 3, 1, 3, 1, 3, 2, 3, 3, 3, 4, 3, 4, 3, 4, 4, 4, 6, 4, 7, 4, 8, 4, 8, 5, 8, 7, 8, 9, 8, 10, 8, 11, 9, 11, 12, 11, 15, 11, 17, 11, 18, 12, 19, 15, 19, 19, 19, 22, 19, 24, 20, 25, 24, 26, 29, 26, 34, 26, 37, 27, 39, 31, 40, 38, 41
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(31) = #{29+2, 20+11, 11+2+2+2+2+2} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116374 Number of partitions of n into parts with digital root = 4.

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 2, 0, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 3, 2, 1, 2, 3, 4, 1, 2, 3, 5, 2, 2, 3, 6, 4, 2, 3, 6, 6, 3, 3, 6, 7, 6, 3, 6, 8, 9, 4, 6, 8, 11, 7, 6, 8, 12, 11, 7, 8, 13, 14, 11, 8, 13, 16, 16, 9, 13, 17, 21, 13, 13, 18, 24, 20, 14, 18, 26
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(39) = #{31+4+4, 22+13+4, 13+13+13} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116375 Number of partitions of n into parts with digital root = 5.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 2, 1, 1, 0, 1, 2, 1, 1, 0, 2, 2, 1, 1, 1, 3, 2, 1, 1, 3, 3, 2, 1, 2, 4, 3, 2, 1, 4, 5, 3, 2, 2, 6, 5, 3, 2, 5, 7, 5, 3, 3, 8, 8, 5, 3, 6, 10, 8, 5, 4, 10, 11, 8, 5, 8, 13, 12, 8, 6, 13, 15, 12, 8, 10, 18, 16, 12, 9, 17, 21, 17
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116376(n) - A116377(n) - A116378(n) - A114099(n).

Examples

			a(42) = #{32+5+5, 23+14+5, 14+14+14} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116377 Number of partitions of n into parts with digital root = 7.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 1, 0, 1, 0, 2, 0, 2, 1, 1, 1, 0, 2, 0, 3, 1, 3, 1, 1, 2, 0, 3, 1, 4, 1, 3, 2, 1, 3, 1, 5, 1, 5, 2, 4, 3, 2, 5, 1, 6, 2, 7, 3, 5, 5, 2, 7, 2, 9, 3, 9, 5, 6, 7, 3, 10, 3, 12, 5, 11, 7, 7, 11, 4, 14, 5, 16, 7, 14
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116378(n) - A114099(n).

Examples

			a(48) = #{34+7+7, 25+16+7, 16+16+16} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]

A116378 Number of partitions of n into parts with digital root = 8.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 2, 1, 0, 0, 0, 0, 1, 1, 2, 2, 1, 0, 0, 0, 1, 1, 2, 3, 3, 1, 0, 0, 1, 1, 2, 3, 4, 3, 1, 0, 1, 1, 2, 3, 5, 5, 4, 1, 1, 1, 2, 3, 5, 6, 7, 4, 2, 1, 2, 3, 5, 7, 9, 8, 6, 2, 2, 3, 5, 7, 10, 11, 11, 6, 3, 3, 5, 7, 11, 13
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 12 2006

Keywords

Comments

a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A114099(n).

Examples

			a(51) = #{35+8+8, 26+17+8, 17+17+17} = 3.
		

Crossrefs

Cf. A010888.
A147706. [From Reinhard Zumkeller, Nov 11 2008]
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