A277894 a(n) = the largest k < n for which A277892(k) = A277892(n), 0 if no such number exists, a(0) = a(1) = 0.

0, 0, 0, 0, 3, 0, 4, 0, 6, 5, 8, 0, 9, 0, 12, 14, 15, 0, 10, 0, 16, 20, 18, 0, 22, 7, 21, 26, 27, 0, 24, 0, 30, 25, 28, 33, 34, 0, 36, 38, 32, 0, 40, 0, 35, 44, 42, 0, 39, 11, 48, 45, 50, 0, 46, 51, 54, 55, 49, 0, 57, 0, 60, 62, 52, 58, 56, 0, 63, 68, 66, 0, 70, 0, 64, 74, 69, 65, 75, 0, 76, 80, 78, 0, 81, 84, 82, 86, 72, 0, 87, 77, 85, 13, 92, 91, 88, 0

Offset

0,5

Links

Antti Karttunen, Table of n, a(n) for n = 0..10000 (computed from the 10000 term b-file provided by Hans Havermann for A277892)

Formula

For n >= 3, a(A277893(n)) = n.

Prog

(Scheme) (define (A277894 n) (cond ((<= n 2) 0) (else (let ((v (A277892 n))) (let loop ((k (- n 1))) (cond ((= 1 k) 0) ((= (A277892 k) v) k) (else (loop (- k 1)))))))))

Crossrefs

Cf. A277892, A277893, A277895.

Cf. A008578 (gives the positions of zeros after a(0)).

Sequence in context: A364067 A246691 A066705 * A027636 A371737 A173425

Adjacent sequences: A277891 A277892 A277893 * A277895 A277896 A277897

Keyword

nonn

Author

Antti Karttunen, Nov 08 2016

Status

approved