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 25 results. Next

A111618 First lower diagonal of A109626.

Original entry on oeis.org

1, 3, 2, 5, 3, 7, 4, 9, 10, 11, 6, 13, 14, 15, 8, 17, 9, 19, 10, 21, 11, 23, 12, 25, 26, 27, 14, 29, 30, 31, 16, 33, 17, 35, 18, 37, 38, 39, 20, 41, 42, 43, 22, 45, 46, 47, 48, 49, 50, 51, 52, 53, 27, 55, 56, 57, 29, 59, 30, 61, 31, 63, 32, 65, 66, 67, 34, 69, 70, 71, 72, 73, 74
Offset: 2

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Author

Keywords

Comments

The odd-indexed bisection is a(2n+1)=2n+1.
The even-indexed bisection: A111619.

Crossrefs

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 80}]]; g[n_, m_] := f[n][[m]]; Table[ g[n, n - 1], {n, 2, 74}]

A111615 Third upper diagonal of the array in A109626.

Original entry on oeis.org

1, 2, 3, 4, 5, 3, 7, 8, 9, 5, 11, 12, 13, 14, 15, 16, 17, 9, 19, 10, 21, 11, 23, 24, 25, 26, 27, 28, 29, 15, 31, 32, 33, 17, 35, 18, 37, 19, 39, 40, 41, 42, 43, 22, 45, 46, 47, 48, 49, 25, 51, 26, 53, 54, 55, 28, 57, 29, 59, 60, 61, 31, 63, 64, 65, 66, 67, 68, 69, 70, 71, 36, 73
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A109626.

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 80}]]; g[n_, m_] := f[n][[m]]; Table[ g[n, n + 3], {n, 74}]

A111607 Fourth column of A109626.

Original entry on oeis.org

1, 2, 3, 3, 5, 3, 7, 2, 9, 10, 11, 9, 13, 7, 15, 4, 17, 18, 19, 15, 21, 11, 23, 6, 25, 26, 27, 21, 29, 15, 31, 8, 33, 34, 35, 27, 37, 19, 39, 10, 41, 42, 43, 33, 45, 23, 47, 12, 49, 50, 51, 39, 53, 27, 55, 14, 57, 58, 59, 45, 61, 31, 63, 16, 65, 66, 67, 51, 69, 35, 71, 18, 73, 74, 75
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A109626.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 102);
    p:= func< x | x*(1+2*x+3*x^2+3*x^3 +5*x^4 +3*x^5 +7*x^6 +2*x^7 +7*x^8 +6*x^9 +5*x^10 +3*x^11 +3*x^12 +x^13 +x^14)/(1-x^8)^2 >;
    Coefficients(R!( p(x) )); // G. C. Greubel, Jan 29 2025
    
  • Mathematica
    (* First program *)
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 128}]]; g[n_, m_] := f[n][[m]]; Table[g[n, 4 + 1], {n, 75}]
    (* Second program *)
    CoefficientList[Series[(1+2*x+3*x^2+3*x^3+5*x^4+3*x^5+7*x^6+2*x^7+7*x^8 +6*x^9+5*x^10+3*x^11+3*x^12+x^13+x^14)/(1-x^8)^2, {x,0,100}], x] (* G. C. Greubel, Jan 29 2025 *)
  • SageMath
    def p(x): return x*(1+2*x+3*x^2+3*x^3 +5*x^4 +3*x^5 +7*x^6 +2*x^7 +7*x^8 +6*x^9 +5*x^10 +3*x^11 +3*x^12 +x^13 +x^14)
    def A111607_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( p(x)/(1-x^8)^2 ).list()
    a=A111607_list(101); a[1:] # G. C. Greubel, Jan 29 2025

Formula

G.f.: x*(1 + 2*x + 3*x^2 + 3*x^3 + 5*x^4 + 3*x^5 + 7*x^6 + 2*x^7 + 7*x^8 + 6*x^9 + 5*x^10 + 3*x^11 + 3*x^12 + x^13 + x^14)/(1-x^8)^2.

A111627 T(2n, n+2)/n of A109626.

Original entry on oeis.org

1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2
Offset: 1

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Author

Keywords

Comments

A sequence of just 1's and 2's.

Crossrefs

Cf. A109626.

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 128}]]; g[n_, m_] := f[n][[m]]; Table[ g[2n, n + 2]/n, {n, 52}]

A111605 Determinant of the upper left n X n elements of the array T(n, m) in A109626.

Original entry on oeis.org

1, 1, 2, 2, 8, -40, 144, 2448, -17280, -71424, 0, 1198080, 0, -18063360, 418037760, -7498137600, -115688079360, -587977850880, 12300343050240, -540240522117120, -36548032147292160, 487948583538524160, -2339225182084792320
Offset: 1

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Author

Keywords

Comments

a(n)=0 for n's: 11, 13, 29, 31, 34, 35, 36, 37, 38, 39, 41, 43, 46, 47, 48, 49, 50, 51, 53,59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, 73, 74, 75, 76, 77, 78, 79, 80

Crossrefs

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 32}]]; g[n_, m_] := f[n][[m]]; Table[ Det[ Table[ g[i, j], {i, n}, {j, n}]], {n, 23}]

A111606 Determinant of the upper left n X n elements excluding its first row and column of the Array T(n,m) in A109626.

Original entry on oeis.org

2, 3, 0, 10, -48, 168, 3456, -29376, -178560, 0, 2995200, 0, -45158400, 1045094400, -14636482560, -122918584320, -370845941760, 12983695441920, -1545691830681600, -62521904633610240, 785989658251100160, -2445553599452282880
Offset: 1

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Author

Keywords

Comments

a(n)=0 for n's, (one less than those in A111605): 3, 10, 12, 28, 30, 33, 34, 35, 36, 37, 38, 40, 42, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 72, 73, 74, 75, 76, 77, 78, 79

Crossrefs

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 32}]]; g[n_, m_] := f[n][[m]]; Table[ Det[ Table[ g[i, j], {i, 2, n}, {j, 2, n}]]{n, 23}]

A111608 Sixth column of A109626.

Original entry on oeis.org

1, 1, 3, 4, 5, 6, 7, 4, 3, 5, 11, 4, 13, 14, 10, 8, 17, 3, 19, 20, 21, 22, 23, 12, 25, 13, 9, 28, 29, 10, 31, 16, 22, 17, 35, 24, 37, 38, 39, 20, 41, 21, 43, 44, 15, 46, 47, 40, 49, 25, 34, 52, 53, 36, 55, 28, 57, 29, 59, 60, 61, 62, 21, 32, 65, 55, 67, 68, 46, 70, 71, 12, 73, 37
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A109626.

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 128}]]; g[n_, m_] := f[n][[m]]; Table[g[n, 6 + 1], {n, 74}]

Formula

G.f.: Q(x)/(1-x^72)^2 where Q(x) is 142-degree polynomial: Q(x)=1+x+3x^2+4x^3+5x^4+6x^5+7x^6+4x^7+...

A111609 Eighth column of A109626.

Original entry on oeis.org

1, 2, 3, 1, 5, 3, 7, 7, 9, 10, 11, 12, 13, 7, 15, 10, 17, 18, 19, 15, 21, 11, 23, 9, 25, 26, 27, 14, 29, 15, 31, 4, 33, 34, 35, 9, 37, 19, 39, 35, 41, 42, 43, 44, 45, 23, 47, 30, 49, 50, 51, 39, 53, 27, 55, 21, 57, 58, 59, 30, 61, 31, 63, 8, 65, 66, 67, 17, 69, 35, 71, 63, 73, 74, 75
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A109626.

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 128}]]; g[n_, m_] := f[n][[m]]; Table[ g[n, 8 + 1], {n, 111}]

A111610 Ninth column of A109626.

Original entry on oeis.org

1, 2, 3, 4, 5, 4, 7, 8, 1, 10, 11, 8, 13, 14, 10, 16, 17, 2, 19, 20, 14, 22, 23, 24, 25, 26, 3, 28, 29, 10, 31, 32, 33, 34, 35, 4, 37, 38, 13, 40, 41, 14, 43, 44, 5, 46, 47, 48, 49, 50, 17, 52, 53, 6, 55, 56, 57, 58, 59, 40, 61, 62, 7, 64, 65, 44, 67, 68, 46, 70, 71, 8, 73, 74, 50
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A109626.

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 128}]]; g[n_, m_] := f[n][[m]]; Table[ g[n, 9 + 1], {n, 75}]

A111611 Tenth column of A109626.

Original entry on oeis.org

1, 1, 3, 4, 4, 6, 7, 8, 9, 3, 11, 6, 13, 14, 15, 8, 17, 9, 19, 20, 21, 22, 23, 24, 5, 13, 27, 14, 29, 6, 31, 16, 33, 17, 14, 36, 37, 38, 39, 16, 41, 21, 43, 22, 27, 46, 47, 24, 49, 5, 51, 52, 53, 54, 44, 56, 57, 29, 59, 18, 61, 62, 63, 32, 65, 33, 67, 68, 69, 70, 71, 72, 73, 37, 15
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A109626.

Programs

  • Mathematica
    f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[a[j], {j, 0, 128}]]; g[n_, m_] := f[n][[m]]; Table[g[n, 10 + 1], {n, 75}]
Showing 1-10 of 25 results. Next