A111315 Positions where A109890(n) = Sum_{i = 1..n-1} A109890(i).

3, 4, 222, 232, 279, 568, 634, 844, 1307, 1704, 2016, 2050, 2164, 2325, 2701, 3130, 3225, 3322, 3524, 4673, 6007, 6692, 7141, 7221, 7954, 8689, 11051, 11898, 13959, 14166, 16192, 17078, 17220, 17521, 18071, 22324, 22414, 24757, 28290, 28979

Offset

1,1

Comments

These are the positions where A109735(n) = 2*A109735(n-1), or equally, where A111241(n) = 1.

Links

Table of n, a(n) for n=1..40.

Prog

(PARI) s = 3; S = Set([1, 2]); i = 3; while (1, d = divisors(s); j = 1; while (setsearch(S, d[j]), j++); n = d[j]; if (n == s, print(i)); s += n; S = setunion(S, Set(n)); i++); \\ David Wasserman, Jan 09 2009

Crossrefs

Cf. A109890, A109735, A111316, A111241.

Sequence in context: A012861 A349885 A042485 * A042711 A195566 A348278

Adjacent sequences: A111312 A111313 A111314 * A111316 A111317 A111318

Keyword

nonn

Author

N. J. A. Sloane, Nov 04 2005

Extensions

More terms from David Wasserman, Jan 09 2009

Status

approved