A302849 Permutation of natural numbers: a(1) = 1, a(2) = 2; for n > 2, a(n) = A064989(4+A003961(n-2)).

1, 2, 3, 5, 4, 11, 7, 17, 6, 29, 23, 9, 13, 25, 10, 31, 22, 39, 19, 73, 8, 61, 53, 41, 14, 137, 47, 21, 82, 101, 15, 107, 37, 187, 38, 59, 16, 227, 12, 71, 83, 191, 43, 121, 26, 49, 173, 55, 34, 401, 27, 149, 28, 151, 20, 373, 51, 205, 65, 89, 33, 161, 67, 57, 116, 727, 74, 197, 18, 45, 139, 129, 35, 445, 79, 113, 158, 199, 50, 155, 46, 569, 403, 85, 58

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Index entries for sequences that are permutations of the natural numbers

Index entries for sequences computed from indices in prime factorization

Formula

a(1) = 1, a(2) = 2; for n > 2, a(n) = A064989(4+A003961(n-2)).

Prog

(PARI)
A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)};
A302849(n) = if(n<=2, n, A064989(4+A003961(n-2)));

Crossrefs

Cf. A302850 (inverse).

Cf. A003961, A064989, A302847.

Sequence in context: A355065 A213900 A213648 * A193971 A258861 A171038

Adjacent sequences: A302846 A302847 A302848 * A302850 A302851 A302852

Keyword

nonn

Author

Antti Karttunen, Apr 26 2018

Status

approved