A377472 First differences of Colombian or self numbers A003052.

2, 2, 2, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 11, 2, 11, 11, 11, 11, 11, 11, 11, 11, 15, 11

Offset

1,1

Comments

Most terms are equal to 11.

Up to a(103) = 15, the only exceptions are a(n) = 2 for n = 1, 2, 3, 4, 14, 24, ..., 94.

Then a(n) = 2 for n = 112, 122, ..., 192, and a(201) = 15.

Then a(n) = 2 for n = 210, 220, ..., 290, and a(299) = 15.

This pattern repeats 8 times, with a(n) = 15 for n = 397, 495, ..., 887.

Then a(984) = 28, after which the previous pattern resumes, with a(n) = 2 for n = 992, 1002, ..., 1072, then a(n) = 15 for n = 1081, 1179, ..., 1865.

This larger pattern continues with a(n) = 28 for n = 1962, 2940, 3918, ..., 8808.

A still larger pattern starts at a(9785) = 41, after which the previous pattern repeats with a(9881) = 15, later a(10762) = 28 etc.

Links

Table of n, a(n) for n=1..104.

Formula

a(n) = A003052(n+1) - A003052(n).

a(n) = A163139(n) + 1 = A163128(n+1) - A163128(n) + 1. - Max Alekseyev, Jan 02 2025

Prog

(PARI) A377472_upto(N=99)={my(o, L=List()); for(n=1+o=1, oo, if(is_A003052(n), listput(L, n-o); o=n; #L<N||break)); L}

Crossrefs

Cf. A003052 (Colombian or self numbers), A377473 (range of this sequence), A377474 (indices where new terms appear), A163128, A163139.

Sequence in context: A164918 A147822 A316497 * A084961 A226398 A248768

Adjacent sequences: A377469 A377470 A377471 * A377473 A377474 A377475

Keyword

nonn

Author

M. F. Hasler, Oct 29 2024

Status

approved