A333548 - OEIS

A333548

Numbers k such that A005132(k-1) = k.

3, 11, 39, 248, 844, 2752, 57071, 58056875

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OFFSET

1,1

COMMENTS

Subtracting 1 from k gives the index of a term A005132(k-1) = k in Recamán's sequence A005132 such that subtracting k would reach 0. This is not permitted, so we must add k instead, obtaining A005132(k) = 2*k.

If A005132(k-1) = k, A005132(k) = 2*k. The converse is not always true. For example, A005132(75) = 228 and A005132(76) = 228 - 76 = 152. - Seiichi Manyama, May 02 2020

LINKS

Table of n, a(n) for n=1..8.

Index entries for sequences related to Recamán's sequence

EXAMPLE

A005132(10)=11, so 11 is a term (and A005132(11)=22).

PROG

(Python)

A333548_list, A005132_set, y = [], {0}, 0

for n in range(1, 10**10):

y -= n

if y <= 0 or y in A005132_set:

y += 2*n