A373236 - OEIS

A373236

Relative of Hofstadter Q-sequence: a(n) = max(0, n+3201) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0.

6, 3202, 3203, 3204, 9, 3205, 3206, 3207, 12, 3208, 3209, 3210, 15, 3211, 3212, 17, 3214, 18, 3214, 3216, 3217, 22, 21, 6413, 6407, 9, 18, 6422, 6425, 3210, 22, 3231, 3236, 3214, 27, 36, 3238, 6412, 3205, 39, 3239, 3245, 3209, 42, 3241, 3248, 16, 3240, 3248, 3228, 40, 3240, 55, 6426, 3217, 46, 3250, 3261, 25, 38, 58, 12855, 6416, 3205

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OFFSET

1,1

COMMENTS

Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then match A000027 for its first 3201 terms.

This sequence has exactly 3725 terms (of positive index). a(3725) = 0, so an attempt to calculate a(3726) would refer to itself.

Without the convention that a(n) = 0 for n <= -3201, this sequence would have exactly 24 terms (of positive index), since computing a(25) refers to a(-6388).

If 3201 in this sequence's definition is replaced by any larger number congruent to 2 mod 7, the behavior is essentially the same, though the quasilinear part (see Formula section) lasts longer.

LINKS

Nathan Fox, Table of n, a(n) for n = 1..3725

FORMULA

If the index is between 67 and 3199 (inclusive), then a(7n) = 7n+2, a(7n+1) = 7n+3203, a(7n+2) = 7n+3205, a(7n+3) = 7, a(7n+4) = 2n+6447, a(7n+5) = n+6395, a(7n+6) = 3199.

CROSSREFS

Cf. A005185, A267501, A278055, A373234, A373235, A373237, A373238, A274058, A373239.

Sequence in context: A265869 A274083 A079183 * A030245 A247965 A172955

Adjacent sequences: A373233 A373234 A373235 * A373237 A373238 A373239

KEYWORD

nonn,fini,full

AUTHOR

Nathan Fox, May 28 2024

STATUS

approved