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 10 results.

A203269 Row sums of triangle A202917.

Original entry on oeis.org

1, 2, 8, 4, 132, 24, 1556, 88, 5364, 168, 5612, 136, 1128168, 28656, 86804, 1672, 3434920, 48080, 173886368, 2462176, 4093653652, 62126504, 4292224444, 10991336, 182512332988, 4948498616
Offset: 0

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Comments

If p is prime, then a(p-1)==2 mod p. At least up to n=251, there is only one nonprime n for which a(n-1)==2 mod n. It is n=18 for which a(18-1)=48080==2(mod 18).

Crossrefs

A175669 Triangle of numerators of coefficients of the polynomial Q^(2)m(n) defined by the recursion Q^(2)_0(n)=1; for m>=1, Q^(2)_m(n) = Sum{i=1..n} i^2*Q^(2)_(m-1)(i). For m>=0, the denominator for all 3*m+1 terms of the m-th row is A202367(m+1).

Original entry on oeis.org

1, 2, 3, 1, 0, 20, 96, 155, 90, 5, -6, 0, 280, 2772, 10518, 18711, 14385, 1323, -2863, -126, 360, 0, 2800, 47040, 323336, 1157760, 2238855, 2050020, 207158, -810600, -58505, 322740, 7956, -45360, 0, 12320, 314160, 3409472, 20401128, 72418826, 150057435, 154651321, 12413874, -101524412, -6408765, 82588957, 3394248, -37374084, -546480, 5443200, 0
Offset: 0

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Consider sequence of sequences of polynomials {Q^(0)_m(x)}, {Q^(1)_m(x)},...,{Q^(r)_m(x)},..., such that in every sequence m=0,1,...
Sequence {Q^(r)m(x)} is defined by the recursion: Q^(r)_0(x)=1; for m>=1 and integer x=n, Q^(r)_m(n)=sum{i=1,...,n}i^rQ^(r)(m-1)(i). By the induction, we see that polynomial Q^(r)_m(x) has degree (r+1)*m. Note that Q^(0)_m(n) is C(n+m-1,m), Q^(1)_m(n)=S(n+m,n), where S(k,l) are Stirling numbers of the second kind. Thus Q^(r)_m(x) is an r-generalization of binomial coefficients and Stirling numbers of the second kind. Moreover, for every r, LCM of denominators of the coefficients of Q^(r)_m(x) generate sequences of factorial type which possess important arithmetic properties. For r=0, it is n!, for r=1, it is A053657, for r=2,3,4 we obtain A202367, A202368, A202369. Denote the general term of the sequence corresponding to a given r by n!^(r) and, for 0<=m<=n, denote C^(r)(n,m)=n!^(r)/(m!^(r)*(n-m)!^(r). Then, for the "r-Pascal triangle", we have the following conjectural regularity: if a prime p==1 mod r, then the ((p-1)/r)-th row contains two 1's and numbers multiple of p. Cf. triangles A202917, A202941.

Examples

			The sequence of polynomials begins:
Q^(2)_0=1,
Q^(2)_1=(2*x^3+3*x^2+x)/6,
Q^(2)_2=(20*x^6+96*x^5+155*x^4+90*x^3+5*x^2-6*x)/360,
Q^(2)_3=(280*x^9+2772*x^8+10518*x^7+18711*x^6+14385*x^5+1323*x^4-2863*x^3 -126*x^2+360*x)/45360.
		

Crossrefs

Formula

Q^(2)_n(1)=1.

A202941 For n>=0, let n!^(2)=A202367(n+1) and, for 0<=m<=n, C^(2)(n,m)=n!^(2)/(m!^(2)*(n-m)!^(2)). The sequence gives triangle of numbers C^(2)(n,m) with rows of length n+1.

Original entry on oeis.org

1, 1, 1, 1, 10, 1, 1, 21, 21, 1, 1, 20, 42, 20, 1, 1, 11, 22, 22, 11, 1, 1, 2730, 3003, 2860, 3003, 2730, 1, 1, 1, 273, 143, 143, 273, 1, 1
Offset: 0

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Conjecture. If p is an odd prime, then the ((p-1)/2)-th row contains two 1's and (p-3)/2 numbers multiple of p.
See also comments in A175669 and A202917.

Examples

			Triangle begins
n/m.|..0.....1.....2.....3.....4.....5.....6.....7
==================================================
.0..|..1
.1..|..1.....1
.2..|..1....10.....1
.3..|..1....21 ...21.....1
.4..|..1....20....42....20.....1
.5..|..1....11....22....22....11.....1
.6..|..1..2730..3003..2860..3003..2730.....1
.7..|..1.....1...273...143...143...273.....1.....1
.8..|
		

Crossrefs

Formula

If conjectural formula in A202367 is true, then A007814(C^(2)(n,m)) =A007814(C(n,m)).

A203278 Row sums of triangle A202941.

Original entry on oeis.org

1, 2, 12, 44, 84, 68, 14328, 836, 24040, 1231088, 31063252, 5495668, 2474249308, 4505692, 130544952, 2741953536, 6519198872, 11977808, 2197436928400, 5058240848, 11783977054420, 363453226568756, 135517101268864, 6345558675936, 67883449330825012, 1419845303575428
Offset: 0

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Comments

Conjecture. If p is odd prime, then a((p-1)/2)==2 (mod p)

Crossrefs

A203484 For n>=0, let n!^(3) = A202368(n+1) and, for 0<=m<=n, C^(3)(n,m) = n!^(3)/(m!^(3)*(n-m)!^(3)). The sequence gives triangle of numbers C^(3)(n,m) with rows of length n+1.

Original entry on oeis.org

1, 1, 1, 1, 42, 1, 1, 5, 5, 1, 1, 1092, 130, 1092, 1, 1, 1, 26, 26, 1, 1, 1, 11970, 285, 62244, 285, 11970, 1, 1, 11, 3135, 627, 627, 3135, 11, 1
Offset: 0

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Conjecture. If p is prime of the form 3*k+1, then the k-th row contains two 1's and k-1 numbers multiple of p; if p is prime of the form 3*k+2, then the (2*k+1)-th row contains two 1's and 2*k numbers multiple of p.

Examples

			Triangle begins
n/m.|..0.....1.....2.....3.....4.....5.....6.....7
==================================================
.0..|..1
.1..|..1......1
.2..|..1.....42.....1
.3..|..1......5 ....5......1
.4..|..1...1092...130...1092.....1
.5..|..1......1....26.....26.....1......1
.6..|..1..11970...285..62244...285..11970....1
.7..|..1.....11..3135....627...627...3135...11.....1
.8..|
		

Crossrefs

Formula

Conjecture. A007814(C^(3)(n,m)) = A007814(C(n,m)).

A178473 For n>=0, let n!^(4) = A202369(n+1) and, for 0<=m<=n, C^(4)(n,m) = n!^(4)/(m!^(4)*(n-m)!^(4)). The sequence gives triangle of numbers C^(4)(n,m) with rows of length n+1.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 273, 273, 1, 1, 68, 9282, 68, 1, 1, 55, 1870, 1870, 55, 1, 1, 546, 15015, 3740, 15015, 546, 1, 1, 29, 7917, 1595, 1595, 7917, 29, 1
Offset: 0

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Conjecture. If p is prime of the form 4*k+1, then the k-th row contains two 1's and k-1 numbers multiple of p; if p is prime of the form 4*k+3, then the (2*k+1)-th row contains two 1's and 2*k numbers multiple of p.

Examples

			Triangle begins
n/m.|..0.....1.....2.....3.....4.....5.....6.....7
==================================================
.0..|..1
.1..|..1......1
.2..|..1......2......1
.3..|..1....273 ...273......1
.4..|..1.....68...9282.....68......1
.5..|..1.....55...1870...1870.....55......1
.6..|..1....546..15015...3740..15015....546....1
.7..|..1.....29...7917...1595...1595...7917...29.....1
.8..|
		

Crossrefs

Formula

Conjecture. A007814(C^(4)(n,m)) = A007814(C(n,m)).

A204087 Reduced Pascal triangle: C_R(n,m) = A003418(n) / max(A003418(m), A003418(n-m)), m=0,...,n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 2, 6, 2, 1, 1, 5, 10, 10, 5, 1, 1, 1, 5, 10, 5, 1, 1, 1, 7, 7, 35, 35, 7, 7, 1, 1, 2, 14, 14, 70, 14, 14, 2, 1, 1, 3, 6, 42, 42, 42, 42, 6, 3, 1, 1, 1, 3, 6, 42, 42, 42, 6, 3, 1, 1, 1, 11, 11, 33, 66, 462, 462, 66, 33, 11, 11, 1
Offset: 0

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Comments

The sixth row is the first one which differs from triangles A080381, A080396.

Examples

			Triangle begins:
n/m.|..0.....1.....2.....3.....4.....5.....6.....7
==================================================
.0..|..1
.1..|..1.....1
.2..|..1.....2.....1
.3..|..1.....3.....3.....1
.4..|..1.....2.....6.....2.....1
.5..|..1.....5....10....10.....5.....1
.6..|..1.....1.....5....10.....5.....1.....1
.7..|..1.....7.....7....35....35.....7.....7.....1
		

Crossrefs

Programs

  • Maple
    g:= proc(n) option remember; `if`(n=0, 1, ilcm(g(n-1), n)) end:
    CR:= proc(n, m) option remember; g(n)/max(g(m), g(n-m)) end:
    seq (seq (CR(n,m), m=0..n), n=0..11); # Alois P. Heinz, Jan 11 2012
  • Mathematica
    g[n_] := g[n] = If[n == 0, 1, LCM[g[n-1], n]]; CR[n_, m_] := CR[n, m] = g[n]/Max[ g[m], g[n-m]]; Table[Table[CR[n, m], {m, 0, n}], {n, 0, 11}] // Flatten (* Jean-François Alcover, Mar 12 2015, after Alois P. Heinz *)

A203498 Row sums of triangle A203484.

Original entry on oeis.org

1, 2, 44, 12, 2316, 56, 86756, 7548, 2745504, 14216, 8303228, 27440, 26755926552, 17777912, 337554780656, 166149231952, 41032825702988, 10165065032, 19445273523788, 559223251080, 52853093762480872, 2217608618621076, 3130076262074284420, 9840817961344
Offset: 0

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Conjecture. If prime p==1 (mod 3), then a((p-1)/3)==2 (mod p); if prime p==2 mod 3, then a((2*p-1)/3)==2 (mod p).

Crossrefs

A203509 Row sums of triangle A178473.

Original entry on oeis.org

1, 2, 4, 548, 9420, 3852, 34864, 19084, 15296, 154560176, 7180221844, 887102780, 211332046788, 71893259484, 20454788424, 5986072942766808, 5988933869570752, 22285488224, 2756032824242080, 17677170921656, 679436626785756, 20936052371230100988
Offset: 0

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Conjecture. If prime p==1 (mod 4), then a((p-1)/4)==2 (mod p); if prime p==3 (mod 4), then a((p-1)/2)==2 (mod p).

Crossrefs

A204088 Row sums of A204087.

Original entry on oeis.org

1, 2, 4, 8, 12, 32, 24, 100, 132, 188, 148, 1168, 708, 3200, 2344, 1488, 2120, 21456, 16596, 222948, 130572, 38196, 29800, 492248, 299096, 529712, 455424, 1143404, 920536, 20232316, 13769088, 226481600, 252603072, 52242944, 40457056, 28671168, 16885280
Offset: 0

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If n is prime, then a(n)==2 mod n. Up to n=200, there are only two composite numbers with such a property: a(49)=623017500436==2 mod 49 and a(51)=391496243228==2 mod 51.

Crossrefs

Showing 1-10 of 10 results.