A269360 Permutation of even numbers: a(n) = 1 + A250469(n).

2, 4, 6, 10, 8, 16, 12, 22, 26, 28, 14, 34, 18, 40, 36, 46, 20, 52, 24, 58, 56, 64, 30, 70, 50, 76, 66, 82, 32, 88, 38, 94, 86, 100, 78, 106, 42, 112, 96, 118, 44, 124, 48, 130, 116, 136, 54, 142, 122, 148, 126, 154, 60, 160, 92, 166, 146, 172, 62, 178, 68, 184, 156, 190, 120, 196, 72, 202, 176, 208, 74, 214, 80, 220, 186, 226, 144

Offset: 1

Author

Antti Karttunen, Mar 13 2016

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384

Crossrefs

Cf. A253886, A250469, A243501.

Cf. also A269863, A269864.

Programs

Mathematica

(* b = A250469 *) b[1] = 1; b[n_] := If[PrimeQ[n], NextPrime[n], m1 = p1 = FactorInteger[n][[1, 1]]; For[ k1 = 1, m1 <= n, m1 += p1; If[m1 == n, Break[]]; If[ FactorInteger[m1][[1, 1]] == p1, k1++]]; m2 = p2 = NextPrime[p1]; For[k2 = 1, True, m2 += p2, If[ FactorInteger[m2][[1, 1]] == p2, k2++]; If[k1+2 == k2, Return[m2]]]];
a[n_] := b[n] + 1;
Array[a, 100] (* Jean-François Alcover, Mar 14 2016 *)

Scheme

(define (A269360 n) (+ 1 (A250469 n)))

Formula

a(n) = 1 + A250469(n).

a(n) = 2 + A253886(n-1).