A137674 Numbers m such that A137671(m) = 1.

1, 2, 5, 13, 35, 84, 198, 414, 960, 1898, 4263, 8556, 18473, 37490, 79526, 159956, 338873, 680306, 1438941, 2869908, 6057397, 12038460, 25300258, 50460684, 105275708, 211424744, 437486956, 879869316, 1810901110, 3642407379, 7495644753, 15038540180, 30957576741

Offset: 1

Author

Reinhard Zumkeller, Feb 05 2008

Keywords

• nonn
• base

Links

• Rémy Sigrist, C program for A137674.

Crossrefs

Cf. A000225, A137671, A137672, A137673.

Programs

C

See Links section.

Mathematica

b[1] = 1; b[n_] := b[n] = Count[Array[s, n - 1], s[n - 1]]; s[n_] := s[n] = DigitCount[b[n], 2, 1]; Select[Range[10000], b[#] == 1 &] (* Amiram Eldar, Jul 27 2023 *)

Formula

A137671(a(n)) = 1.

A137672(a(n)) = 1.

For n > 1: A137671(a(n)-1) = 2^(n-1)-1 = A000225(n-1), A137672(a(n)-1) = n-1, and a(n) = A137673(A137671(a(n)-1)) + 1.

Extensions

More terms from Rémy Sigrist, Jun 28 2019