A309430 - OEIS

A309430

a(n) = a(n-a(n-1)) + a(n-a(n-4)), with a(n) = ceiling(2*n/3) for n <= 7.

1, 2, 2, 3, 4, 4, 5, 6, 6, 7, 7, 8, 9, 9, 10, 10, 11, 11, 12, 13, 13, 13, 14, 14, 15, 16, 16, 17, 17, 18, 19, 19, 19, 20, 20, 21, 21, 22, 23, 23, 24, 24, 25, 25, 26, 26, 26, 27, 27, 28, 29, 29, 30, 30, 31, 31, 32, 33, 33, 33, 34, 34, 35, 36, 36, 37, 37, 38, 38, 38, 39, 39, 40, 41, 41, 41, 42, 42, 43, 44, 44

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OFFSET

1,2

COMMENTS

A slow solution to Hofstadter V recurrence.

Numbers k such that a(k) < A063882(k) are 1654, 1721, 1925, ...

LINKS

Table of n, a(n) for n=1..81.

FORMULA

a(n+1) - a(n) = 0 or 1 for all n >= 1.

PROG

(PARI) q=vector(100); for(n=1, 7, q[n]=ceil(2*n/3)); for(n=8, #q, q[n]=q[n-q[n-1]] +q[n-q[n-4]]); q