A350007 Array read by antidiagonals, n >= 2, m >= 0: T(n,m) is the smallest ludic number L(k) such that all n-th differences of (L(k), ..., L(k+n+m)) are zero, where L is A003309; T(n,m) = 0 if no such number exists.

1, 71, 11, 6392047, 41, 41

Offset

2,2

Comments

Equivalently, T(n,m) is the smallest ludic number L(k) such that there is a polynomial f of degree at most n-1 such that f(j) = L(j) for k <= j <= k+n+m.

T(n,m) = A003309(k), where k is the smallest positive integer such that A350004(n,k+j) = 0 for 0 <= j <= m.

Links

Table of n, a(n) for n=2..7.

Formula

T(n,m) <= T(n-1,m+1).

T(n,m) <= T(n, m+1).

Sum_{j=0..n} (-1)^j*binomial(n,j)*A003309(k+i+j) = 0 for 0 <= i <= m, where A003309(k) = T(n,m).

Example

Array begins:
  n\m|     0        1        2        3        4        5
  ---+---------------------------------------------------
   2 |     1       71  6392047        ?        ?        ?
   3 |    11       41     1111  2176387 61077491 93320837
   4 |    41     1111   545977 27244691 93320837        ?
   5 |    47       91 27244691 93320837        ?        ?
   6 |    91    23309 93320837        ?        ?        ?
   7 |  1361  9899189        ?        ?        ?        ?
   8 |  4261    26233        ?        ?        ?        ?
   9 |   481  7110347        ?        ?        ?        ?
  10 | 46067 79241951        ?        ?        ?        ?
For n = 5 and m = 1, the first seven (n+m+1) consecutive ludic numbers for which all fifth (n-th) differences are 0 are (91, 97, 107, 115, 119, 121, 127), so T(5,1) = 91. The successive differences are (6, 10, 8, 4, 2, 6), (4, -2, -4, -2, 4), (-6, -2, 2, 6), (4, 4, 4), and (0, 0).

Crossrefs

Cf. A350005 (row n = 2), A350006 (column m = 0).

Cf. A003309, A349644 (counterpart for primes), A350003 (counterpart for lucky numbers), A350004.

Sequence in context: A266548 A051324 A317721 * A128856 A033391 A122967

Adjacent sequences: A350004 A350005 A350006 * A350008 A350009 A350010

Keyword

nonn,tabl,more

Author

Pontus von Brömssen, Dec 08 2021

Status

approved