A147871 -id:A147871 - cp's OEIS frontend

A147665 a(n) = a(a(n - 1)) + r(n) for n >= 3, where r(3k) = a(a(k)), r(3k+1) = a(a(k)) and r(3*k+2) = a(n-a(k)), with a(0) = 0 and a(1) = a(2) = 1.

0, 1, 1, 2, 2, 3, 3, 3, 5, 4, 3, 6, 4, 3, 6, 5, 5, 9, 6, 5, 12, 6, 5, 15, 8, 8, 11, 8, 7, 11, 8, 7, 14, 9, 7, 14, 8, 7, 10, 5, 5, 13, 6, 6, 13, 6, 6, 9, 7, 6, 9, 8, 9, 17, 12, 7, 12, 7, 6, 15, 9, 8, 14, 9, 7, 18, 9, 7, 12, 9, 9, 16, 10, 8, 14, 11, 11, 15, 11, 12, 13, 8, 10, 14, 9, 7, 15, 11, 12, 15

Offset: 0

Roger L. Bagula, Nov 09 2008

nonn

G. C. Greubel, Table of n, a(n) for n = 0..1000

Cf. A004001, A140473, A143089, A143091, A147871.

a[n_]:= a[n]= If[n<3, Floor[(n+1)/2], a[a[n-1]] + If[Mod[n, 3]<2, a[a[Floor[n/3]]], a[n - a[Floor[n/3]]]]];
Table[f[n], {n, 0, 100}]

def A147665(n):
    if n <= 2: return [0, 1, 1][n]
    elif n % 3 <= 1: return A147665(A147665(n-1)) + A147665(A147665(n//3))
    else: return A147665(A147665(n-1)) + A147665(n - A147665(n//3))
print([A147665(n) for n in range(100)]) # Oct 18 2009

a(n) = a(a(n - 1)) + r(n) for n >= 3, where r(3*k) = a(a(k)), r(3*k+1) = a(a(k)) and r(3*k+2) = a(n-a(k)), with a(0) = 0 and a(1) = a(2) = 1.

Applied OEIS standards to nomenclature - The Assoc. Editors of the OEIS, Oct 18 2009

Name edited by Petros Hadjicostas, Apr 11 2020

A147953 Expansion of Product_{k > 0} (1 + f(k)*x^k), where f(n) = A147952(n).

Original entry on oeis.org

1, 1, 1, 3, 4, 7, 9, 14, 22, 32, 43, 61, 89, 118, 167, 235, 312, 417, 572, 748, 1006, 1326, 1744, 2283, 2982, 3878, 5048, 6518, 8355, 10786, 13727, 17436, 22173, 28250, 35561, 45008, 56651, 70818, 88992, 111280, 138431, 172284, 214019, 265166, 328127

Offset: 0

Roger L. Bagula, Nov 17 2008

nonn

Cf. A147654, A147655, A147665, A147869, A147871, A147880, A147952.

f[0] = 0; f[1] = 1; f[2] = 1;
f[n_] := f[n] = f[f[n - 2]] + If[Mod[n, 3] == 0,f[f[n/3]], If[Mod[n, 3] == 1, f[f[(n - 1)/3]], f[n - f[(n - 2)/3]]]];
P[x_, n_] := P[x, n] = Product[1 + f[m] x^m, {m, 0, n}];
Take[CoefficientList[P[x, 45], x],45]
(* Program edited and corrected by Petros Hadjicostas, Apr 12 2020 *)

a(n) = [x^n] Product_{k > 0} (1 + f(k)*x^k), where f(1) = f(2) = 1, and for m >= 3, f(m) = f(f(m-2)) + r(m), where r(m) = f(f(floor(m/3)) when m == 0 or 1 (mod 3) and = f(m - f(floor(m/3))) when m == 2 (mod 3).

Various sections edited by Petros Hadjicostas, Apr 12 2020

A147955 Expansion of Product_{k >= 0} (1 + A147954(k)*x^k).

Original entry on oeis.org

1, 1, 1, 3, 4, 7, 10, 15, 22, 34, 46, 65, 93, 123, 175, 245, 324, 425, 592, 764, 1015, 1352, 1750, 2266, 2931, 3793, 4897, 6259, 7930, 10080, 12788, 16047, 20176, 25482, 31641, 39630, 49306, 60932, 75552, 93432, 114597, 141013, 173259, 211595, 258933, 316375, 384359, 466927, 566443

Offset: 0

Roger L. Bagula, Nov 17 2008

nonn

			From _Petros Hadjicostas_, Apr 21 2020: (Start)
Let f(m) = A147954(m). Using the strict partitions of n (see A000009), we get:
a(1) = f(1) = 1,
a(2) = f(2) = 1,
a(3) = f(3) + f(1)*f(2) = 2 + 1*1 = 3,
a(4) = f(4) + f(1)*f(3) = 2 + 1*2 = 4,
a(5) = f(5) + f(1)*f(4) + f(2)*f(3) = 3 + 1*2 + 1*2 = 7,
a(6) = f(6) + f(1)*f(5) + f(2)*f(4) + f(1)*f(2)*f(3) = 3 + 1*3 + 1*2 + 1*1*2 = 10,
a(7) = f(7) + f(1)*f(6) + f(2)*f(5) + f(3)*f(4) + f(1)*f(2)*f(4) = 3 + 1*3 + 1*3 + 2*2 + 1*1*2 = 15. (End)

Cf. A000009, A004001, A147655, A147665, A147871, A147954.

f := proc(n) local v; option remember;
if n = 0 then v := 0; end if;
if n = 1 or n = 2 then v := 1; end if;
if 3 <= n and n <= 5 then v := f(f(n - 1)) + f(n - f(n - 1)); end if;
if 6 <= n and 5 <> n mod 6 then v := f(f(n - 1)) + f(f(floor(n/6))); end if;
if 6 <= n and 5 = n mod 6 then v := f(f(n - 1)) + f(n - f(floor(n/6))); end if; v; end proc; # this gives sequence A147954
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
      b(n, i-1) +`if`(i>n, 0, b(n-i, i-1)*f(i))))
    end:
a:= n-> b(n$2):
seq(a(n), n=0..50); # Petros Hadjicostas, Apr 21 2020 (using Alois P. Heinz's program from A147655)

f[0] = 0; f[1] = 1; f[2] = 1;
f[n_] := f[n] =
   f[f[n - 1]] +
    If[n < 6, f[n - f[n - 1]],
     If[Mod[n, 6] == 0, f[f[n/6]],
      If[Mod[n, 6] == 1, f[f[(n - 1)/6]],
       If[Mod[n, 6] == 2, f[f[(n - 2)/6]],
        If[Mod[n, 6] == 3, f[f[(n - 3)/6]],
         If[Mod[n, 6] == 4, f[f[(n - 4)/6]], f[n - f[(n - 5)/6]]]]]]]];
P[x_, n_] := P[x, n] = Product[1 + f[m]*x^m, {m, 0, n}];
Take[CoefficientList[P[x, 45], x], 45]

a(n) = [x^n] Product_{k >= 0} (1 + A147954(k)*x^k).

a(n) = Sum_{(b_1,...,b_n)} f(1)^b_1 * f(2)^b_2 * ... * f(n)^b_n, where f(m) = A147954(m), and the sum is taken over all lists (b_1,...,b_n) with b_j in {0,1} and Sum_{j=1..n} j*b_j = n. - Petros Hadjicostas, Apr 21 2020

Name, data, and Mathematica program edited and corrected by Petros Hadjicostas, Apr 21 2020

A147879 Expansion of Product_{k>=1} (1 + x^k*A005185(k)).

Original entry on oeis.org

1, 1, 1, 3, 5, 8, 12, 21, 29, 49, 73, 105, 162, 236, 338, 502, 706, 984, 1441, 1998, 2800, 3934, 5472, 7407, 10210, 14053, 19066, 25986, 35134, 47010, 63739, 85008, 112610, 150861, 200133, 264838, 349587, 459970, 602763, 792220, 1034136, 1345530

Offset: 0

Roger L. Bagula, Nov 16 2008

nonn

Cf. A004001, A005185, A147559, A147654, A147655, A147665, A147869, A147871.

f[n_Integer?Positive] := f[n] = f[n - f[n - 1]] + f[n - f[n - 2]]; f[0] = 0; f[1] = f[2] = 1; (* A005185 *)
nmax = 41; CoefficientList[Series[Product[(1 + f[k] * x^k), {k, 1, nmax}], {x, 0, nmax}], x] (* Georg Fischer, Dec 10 2020 *)

\\ here B(n) is A005185 as vector.
B(n)={my(A=vector(n, k, 1)); for(k=3, n, A[k]= A[k-A[k-1]]+ A[k-A[k-2]]); A}
seq(n)=my(v=B(n)); {Vec(prod(k=1, #v, 1 + x^k*v[k] + O(x*x^n)))} \\ Andrew Howroyd, Dec 10 2020

Definition corrected by Georg Fischer, Dec 10 2020

A152006 Expansion of Product_{k > 0} (1 + f(k)*x^k), where f(1) = 1 and f(m) = prime(m-1) for m >= 2.

Original entry on oeis.org

1, 1, 2, 5, 8, 18, 34, 63, 102, 203, 336, 589, 999, 1675, 2799, 4768, 7561, 12224, 20513, 31724, 51621, 81976, 128560, 199192, 312536, 482806, 744847, 1147952, 1755931, 2649474, 4051413, 6069450, 9105323, 13747364, 20335077, 30508629, 45198631

Offset: 0

Roger L. Bagula, Nov 19 2008

nonn

Cf. A147557, A147654, A147655, A147665, A147869, A147871, A147880, A147953.

f[n_] = If[n < 2, n, Prime[n - 1]];
P[x_, n_] := P[x, n] = Product[1 + f[m]*x^m, {m, 0, n}];
Take[CoefficientList[P[x, 37], x],37]
(* Program edited and corrected by Petros Hadjicostas, Apr 12 2020 *)

a(n) = [x^n] Product_{k > 0} (1 + f(k)*x^k), where f(1) = 1 and f(m) = prime(m-1) for m >= 2.

Various sections edited by Petros Hadjicostas, Apr 12 2020

cp's OEIS Frontend

A147665 a(n) = a(a(n - 1)) + r(n) for n >= 3, where r(3*k) = a(a(k)), r(3*k+1) = a(a(k)) and r(3*k+2) = a(n-a(k)), with a(0) = 0 and a(1) = a(2) = 1.

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A147953 Expansion of Product_{k > 0} (1 + f(k)*x^k), where f(n) = A147952(n).

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A147955 Expansion of Product_{k >= 0} (1 + A147954(k)*x^k).

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A147879 Expansion of Product_{k>=1} (1 + x^k*A005185(k)).

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A152006 Expansion of Product_{k > 0} (1 + f(k)*x^k), where f(1) = 1 and f(m) = prime(m-1) for m >= 2.

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A147665 a(n) = a(a(n - 1)) + r(n) for n >= 3, where r(3k) = a(a(k)), r(3k+1) = a(a(k)) and r(3*k+2) = a(n-a(k)), with a(0) = 0 and a(1) = a(2) = 1.