login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A232097 a(n) = least k such that 1+2+3+...+k (k-th triangular number) is a multiple of n!; a(n) = least k such that A232096(k) >= n. 4
1, 3, 3, 15, 15, 224, 224, 4095, 76544, 512000, 9511424, 20916224, 410572799, 672358400, 2985984000, 1004293914624, 1004293914624, 78942076928000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = least k such that A232096(k) >= n.

Each A000217(a(n)) is divisible by A118381(n).

Each a(n) or a(n)+1 is divisible by 2*A060818(n) = A086117(n+1).

Each a(n) or a(n)+1 is divisible by A060828(n), and similarly for all the higher bases.

If we were instead searching for the first occurrence where A232096 gets a new distinct value, then we would have another sequence, b, which would start as: 1, 3, 4, 15, 32, 224, 575, 4095, ... as those distinct values do not appear in monotone order, being for n>=1, A232096(b(n)) = 1, 3, 2, 5, 4, 7, 6, 8, 9, 10, ...

LINKS

Table of n, a(n) for n=1..18.

PROG

(Scheme)

(define (A232097 n) (let ((increment (* 2 (A060818 n)))) (let loop ((k increment)) (cond ((>= (A232096 (- k 1)) n) (- k 1)) ((>= (A232096 k) n) k) (else (loop (+ k increment)))))))

;; Alternative, very naive and slow version:

(define (A232097v2 n) (let loop ((k 1)) (if (>= (A232096 k) n) k (loop (+ 1 k)))))

CROSSREFS

Cf. A000217, A232096. A232101 gives the ratio A000217(a(n)) / n!

Sequence in context: A185275 A055634 A133221 * A110096 A157526 A208229

Adjacent sequences:  A232094 A232095 A232096 * A232098 A232099 A232100

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 18 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 07:51 EDT 2019. Contains 322381 sequences. (Running on oeis4.)