A350005 a(n) is the smallest number that starts an arithmetic progression of n consecutive ludic numbers (A003309), or 0 if no such number exists.

1, 1, 1, 71, 6392047

Offset

1,4

Comments

a(n) is the smallest ludic number A003309(k), such that A260723(k) = A260723(k+1) = ... = A260723(k+n-2).

a(6) > 10^8 (unless a(6) = 0).

Links

Table of n, a(n) for n=1..5.

Example

The first arithmetic progression of 3 consecutive ludic numbers is (1, 2, 3), so a(3) = 1.
The first arithmetic progression of 4 consecutive ludic numbers is (71, 77, 83, 89), so a(4) = 71.
The first arithmetic progression of 5 consecutive ludic numbers is (6392047, 6392077, 6392107, 6392137, 6392167), so a(5) = 6392047.

Crossrefs

From n = 3, first row of A350007.

Cf. A003309, A260723.

Counterparts for other sequences than ludic numbers: A006560 (primes), A228433 (abundant numbers), A231623 (deficient numbers), A276821 (Sophie Germain primes), A330362 (lucky numbers).

Sequence in context: A078915 A144242 A144360 * A230378 A352732 A093176

Adjacent sequences: A350002 A350003 A350004 * A350006 A350007 A350008

Keyword

nonn,more

Author

Pontus von Brömssen, Dec 08 2021

Status

approved