A353592 -id:A353592 - cp's OEIS frontend

A355506 a(n) is the least positive integer not occurring earlier in the sequence such that, if a(m) = a(n)+1, then |m - n| >= a(n).

1, 2, 4, 6, 8, 3, 10, 12, 5, 14, 16, 7, 18, 20, 22, 9, 24, 26, 11, 28, 30, 32, 13, 34, 36, 15, 38, 40, 42, 17, 44, 46, 19, 48, 50, 21, 52, 54, 56, 23, 58, 60, 25, 62, 64, 66, 27, 68, 70, 29, 72, 74, 31, 76, 78, 80, 33, 82, 84, 35, 86, 88, 90, 37, 92, 94, 39, 96, 98, 41, 100, 102, 104, 43, 106

Offset: 1

Ali Sada, Jul 04 2022

nonn

A permutation of the positive integers (or of the nonnegative integers, if prefixed by a(0) = 0). It seems that all the odd numbers occur in order at indices A184119 and the even numbers occur in order at indices A136119, except for the initial 1 and 2. - M. F. Hasler, Jul 04 2022

The graph of the sequence has two "rays", one with slope 0.583 that contains only every third or fourth value, and one with slope 1.42 which contains the other values. - M. F. Hasler, May 09 2025

			The distance between a(3) = 4 and a(9) = 5 is |3 - 9| = 6, which is >= 4.

OEIS Index to sequences related to permutations of the positive (or nonnegative) integers.

Cf. A184119, A136119.

Cf. A353592 (inverse permutation).

{A355506_first(N, U=1/*starting value*/, A=Map())=vector(N, n, my(k=U); while(mapisdefined(A,k) || iferr(n < mapget(A,k-1)+k-1 || n2 && mapdelete(A,U-2); U++); k)} \\ M. F. Hasler, Jul 05 2022

More terms from M. F. Hasler, Jul 04 2022

cp's OEIS Frontend

A355506 a(n) is the least positive integer not occurring earlier in the sequence such that, if a(m) = a(n)+1, then |m - n| >= a(n).

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