A392874 a(n) = A005940(1+n) mod A117366(A005940(1+n)), where A117366 gives the smallest prime greater than the largest prime dividing n, and A005940 is Doudna-sequence.

1, 2, 3, 1, 5, 1, 4, 2, 7, 3, 1, 2, 4, 3, 2, 1, 11, 3, 10, 6, 2, 2, 3, 4, 5, 1, 5, 1, 6, 4, 1, 2, 13, 9, 7, 6, 3, 9, 8, 5, 12, 4, 6, 4, 10, 6, 2, 3, 4, 10, 4, 2, 3, 3, 1, 2, 2, 5, 4, 3, 2, 2, 3, 1, 17, 9, 5, 5, 14, 1, 8, 1, 6, 6, 9, 7, 2, 5, 2, 3, 7, 11, 10, 8, 8, 1, 7, 1, 6, 9, 8, 5, 6, 4, 6, 1, 16, 8, 12, 9, 7

Offset

0,2

Links

Antti Karttunen, Table of n, a(n) for n = 0..16383

Index entries for sequences related to binary expansion of n.

Formula

a(n) = A392865(A005940(1+n)) = A005940(1+n) mod A000040(1+A290251(n)).

a(2^n) = A000040(1+n).

Prog

(PARI) A392874(n) = { my(p=2, t=1); until(!n\=2, if((n%2), (t*=p), p=nextprime(1+p))); (t%nextprime(1+p)); };

Crossrefs

Cf. A000040, A005940, A117366, A290251, A392865.

Cf. also A392866, A392875, A392876 for other similar sequences.

Sequence in context: A200068 A380320 A139764 * A371356 A227643 A249386

Adjacent sequences: A392871 A392872 A392873 * A392875 A392876 A392877

Keyword

nonn,base,easy

Author

Antti Karttunen, Jan 27 2026

Status

approved