A249430 a(n) = Least integer k such that A249431(k) = n, and -1 if no such integer exists.

1, 0, 350, 439, 174, 713, 323, 1923, 1052, 999, 1766, 3749, 2254, 2253, 1934, 3391

Offset

0,3

Comments

a(n) = the least natural number k such that {product of elements on row k of Pascal's triangle} is divisible by (k+n)! but not by (k+n+1)!

Note: a(18) = 3144 and a(24) = 2974. First values k for which A249431(k) = 16 and 17, if they exist, are larger than 4096.

Links

Table of n, a(n) for n=0..15.

Prog

(Scheme) (define (A249430 n) (let loop ((k 0)) (cond ((= n (A249431 k)) k) (else (loop (+ 1 k))))))

Crossrefs

Nonnegative terms are all members of A249434.

Cf. A000142, A001142, A007318, A249151, A249431, A249432.

Sequence in context: A285463 A138944 A043619 * A260763 A109761 A109762

Adjacent sequences: A249427 A249428 A249429 * A249431 A249432 A249433

Keyword

nonn,more

Author

Antti Karttunen, Nov 02 2014

Status

approved