A283487 a(1)=1. a(n)>a(n-1) is the smallest positive integer such that the number of divisors of Sum{k=1..n} a(k) is n.

1, 2, 6, 12, 60, 66, 582, 605, 782, 881, 56052, 56059, 416333, 416591, 425552, 425554, 41247583, 41247675, 303126093, 303126138, 304477309, 304482240, 30081553433, 30081553435, 30710954157, 30711032607, 30712767417, 30712767879, 22692482319857, 22692482320447

Offset

1,2

Links

Table of n, a(n) for n=1..30.

Mathematica

a[1] = 1; a[n_] := a[n]=Module[{an = a[n-1] + 1}, While[DivisorSigma[0, Sum[a[i], {i, n - 1}] + an] != n, an++]; an]; a/@Range[17]

Crossrefs

Cf. A175350.

Sequence in context: A347304 A065887 A072181 * A126915 A328450 A322381

Adjacent sequences: A283484 A283485 A283486 * A283488 A283489 A283490

Keyword

nonn

Author

Ivan N. Ianakiev, Mar 08 2017

Extensions

a(18)-a(30) from Giovanni Resta, Mar 09 2017

Status

approved