A263079 Numbers n for which there does not exist any x > n such that A155043(x) < A155043(n).

1, 2, 3, 4, 6, 8, 9, 10, 12, 14, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 38, 40, 42, 44, 46, 48, 49, 50, 52, 54, 56, 60, 72, 84, 96, 104, 108, 120, 128, 132, 136, 140, 142, 144, 150, 152, 156, 160, 162, 168, 170, 180, 182, 184, 186, 188, 190, 192, 194, 198, 200, 204, 208, 210, 216, 220, 225, 228, 240, 248, 252, 260, 264, 276, 280, 288, 296, 300, 308, 312, 320, 328, 340, 352, 360

Offset

1,2

Comments

Numbers n for which A263077(n) < n.

Numbers n for which A263078(n) is negative.

Numbers n at which point A155043(n) is the greatest lower bound for the rest of its terms from A155043(n) onward.

Links

Antti Karttunen, Table of n, a(n) for n = 1..9165

Example

1 is present because A049820(1) = 0, thus A155043(1) = 1, while all the larger numbers require at least the same number of steps to reach zero.

Mathematica

a[0] = 0; a[n_] := a[n] = 1 + a[n - DivisorSigma[0, n]]; Position[Table[k = 3 n; While[a@ k >= a@ n, k--]; k - n, {n, 200}], _Integer?Negative] // Flatten (* Michael De Vlieger, Oct 13 2015 *)

Prog

(PARI)
n=0; i=0; while(n < 124340, n++; if((A263077(n) < n), i++; write("b263079.txt", i, " ", n)));
\\ Other code as in A263077.
(Scheme, with Antti Karttunen's IntSeq-library)
(define A263079 (MATCHING-POS 1 1 (COMPOSE negative? A263078)))

Crossrefs

Cf. A155043, A261089, A262503, A263077, A263078.

Complement: A263080.

Sequence in context: A280196 A143896 A160719 * A362077 A085451 A240911

Adjacent sequences: A263076 A263077 A263078 * A263080 A263081 A263082

Keyword

nonn

Author

Antti Karttunen, Oct 09 2015

Status

approved