0,1

Sometimes used to gauge the concentration ability of a patient with Alzheimer's disease. The combination of a simple arithmetic operation with an unusual decrement forces the patient to rely on short term memory for the computation. Theoretically, most patients will stop when they get to 2, the psychiatrist might be satisfied with the first five or so terms. In this capacity the sequence is mentioned a few times in the movie "Safe House" (1998) in which Mace Sowell (Patrick Stewart) tries to memorize the sequence and is asked it by the psychiatrist (Hector Elizondo). In real life, other decrements can be used; Fish (1996) suggests 3 and 4.

In the next-to-last episode of "Boston Legal," Denny Crane (William Shatner) is asked this sequence by a doctor while in an MRI machine. He gets confused at 86, following it with 81. (Both Shatner and Stewart have played captain of the Enterprise on TV). [From Wilfredo Lopez (chakotay147138274(AT)yahoo.com), Dec 03 2008]

S. Fish, "Alzheimer's: Caring for Your Loved One, Caring for Yourself", Wheaton, Illinois: Harold Shaw Publishers, 1996, p. 34

Tanya Khovanova, Non Recursions

Intelihealth, Dementia: Overview: Diagnosis.

100 - 7n

First fifteen terms of A017005 backwards.

Sequence in context: A008903 A033420 A020993 this_sequence A096582 A115048 A112525

Adjacent sequences: A115017 A115018 A115019 this_sequence A115021 A115022 A115023

easy,fini,full,nonn

Robert Happelberg (roberthappelberg(AT)yahoo.com), Feb 23 2006