A081382 a(1) = 1, for n > 1 a(n) = Min{x > n, A008472(x) = A008472(n)}.

1, 4, 9, 8, 6, 12, 10, 16, 27, 20, 121, 18, 22, 28, 45, 32, 210, 24, 34, 40, 30, 44, 273, 25, 36, 52, 81, 56, 399, 60, 58, 64, 70, 68, 42, 48, 435, 76, 55, 49, 651, 84, 82, 88, 75, 92, 777, 54, 50, 80, 91, 104, 903, 72, 66, 98, 85, 116, 1645, 63, 118, 124, 90, 128, 77, 117

Offset

1,2

Comments

Differs from A065642, a(n) <= A065642(n).

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Mathematica

ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] spf[x_] := Apply[Plus, ba[x]] Table[Min[Flatten[Position[Table[spf[w], {w, n+1, n^2}]-spf[n], 0]]+n], {n, 1, 100}]

Prog

(Haskell)
a081382 1 = 1
a081382 n = head [x | let sopf = a008472 n, x <- [n+1..], a008472 x == sopf]
-- Reinhard Zumkeller, Jun 12 2015

Crossrefs

Cf. A065642, A008472.

Sequence in context: A199203 A371500 A197580 * A188658 A248803 A019784

Adjacent sequences: A081379 A081380 A081381 * A081383 A081384 A081385

Keyword

nonn

Author

Labos Elemer, Mar 26 2003

Status

approved