A101505 Smallest m such that A101504(m) = n.

0, 2, 3, 4, 6, 7, 10, 11, 15, 20, 25, 26, 32, 33, 40, 49, 57, 58, 67, 68, 78, 91, 102, 103, 115, 132, 145, 162, 176, 177, 192, 193, 209, 230, 247, 272, 290, 291, 310, 335, 355, 356, 377, 378, 400, 429, 452, 453, 477, 514, 539, 572, 598, 599, 626, 667, 695, 732

Offset

1,2

Comments

a(p+1) = a(p) + 1 for primes p.

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Formula

a(n+1) = a(n) + n + 2 - A101504(a(n)+1), a(1) = 1.

Mathematica

a = {0}; mx = last = 1; Do[If[last <= mx, last++, mx = last; last = Plus @@ Divisors[last][[{-2, 2}]]; AppendTo[a, n]], {n, 750}]; a (* Ivan Neretin, Aug 25 2016 *)

Crossrefs

Sequence in context: A055802 A114220 A134519 * A259625 A068713 A218549

Adjacent sequences: A101502 A101503 A101504 * A101506 A101507 A101508

Keyword

nonn

Author

Reinhard Zumkeller, Dec 05 2004

Status

approved