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.

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A368048 a(n) = lcm_{p in Partitions(n)} (Product_{t in p}(t + m)), where m = 2.

Original entry on oeis.org

1, 3, 36, 540, 6480, 136080, 8164800, 24494400, 293932800, 48498912000, 4073908608000, 158882435712000, 9532946142720000, 28598838428160000, 343186061137920000, 612587119131187200000, 7351045429574246400000, 419009589485732044800000, 276546329060583149568000000
Offset: 0

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Author

Peter Luschny, Dec 12 2023

Keywords

Comments

With m = 0, the cumulative radical A048803 is computed, and with m = 1 the Hirzebruch numbers A091137. The general array is A368116. Using the terminology introduced in A368116 a(n) = lcm_{p in P_{2}(n)} Prod(p).

Examples

			Let n = 4. The partitions of 4 are [(4), (3, 1), (2, 2), (2, 1, 1), (1, 1, 1, 1)]. Thus a(4) = lcm([6, 5*3, 4*4, 4*3*3, 3*3*3*3]) = 6480.
		

Crossrefs

Programs

  • SageMath
    def a(n): return lcm(product(r + 2 for r in p) for p in Partitions(n))
    print([a(n) for n in range(20)])

Formula

a(n) = A368092(n) * 2^(n - n mod 2).

A368093 Cumulative products of the generalized Clausen numbers. Array read by ascending antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 3, 12, 6, 1, 1, 9, 24, 12, 1, 5, 5, 135, 720, 60, 1, 1, 25, 5, 405, 1440, 360, 1, 7, 7, 875, 175, 8505, 60480, 2520, 1, 1, 49, 7, 4375, 175, 127575, 120960, 5040, 1, 1, 1, 343, 49, 21875, 875, 382725, 3628800, 15120
Offset: 0

Views

Author

Peter Luschny, Dec 12 2023

Keywords

Comments

A160014 are the generalized Clausen numbers, for m = 0 the formula computes the cumulative radical A048803, and for m = 1 the Hirzebruch numbers A091137.

Examples

			Array A(m, n) starts:
  [0] 1, 1,  2,   6,   12,     60,     360,      2520, ...  A048803
  [1] 1, 2, 12,  24,  720,   1440,   60480,    120960, ...  A091137
  [2] 1, 3,  9, 135,  405,   8505,  127575,    382725, ...  A368092
  [3] 1, 1,  5,   5,  175,    175,     875,       875, ...
  [4] 1, 5, 25, 875, 4375,  21875,  765625,  42109375, ...
  [5] 1, 1,  7,   7,   49,     49,    3773,      3773, ...
  [6] 1, 7, 49, 343, 2401, 184877, 1294139, 117766649, ...
  [7] 1, 1,  1,   1,   11,     11,     143,       143, ...
  [8] 1, 1,  1,  11,   11,    143,    1573,      1573, ...
  [9] 1, 1, 11,  11, 1573,   1573,   17303,     17303, ...
		

Crossrefs

Cf. A160014, A048803 (m=0), A091137 (m=1), A368092 (m=2).

Programs

  • SageMath
    from functools import cache
    def Clausen(n, k):
        return mul(s for s in map(lambda i: i+n, divisors(k)) if is_prime(s))
    @cache
    def CumProdClausen(m, n):
        return Clausen(m, n) * CumProdClausen(m, n - 1) if n > 0 else 1
    for m in range(10): print([m], [CumProdClausen(m, n) for n in range(8)])

Formula

A(m, n) = A160014(m, n) * A(m, n - 1) for n > 0 and A(m, 0) = 1.
Showing 1-2 of 2 results.