cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A349940 Terms of A339863 that are congruent to 5 modulo 6: numbers k == 5 (mod 6) such that A005179(k-1) > A005179(k) < A005179(k+1) >A005179(k+2) < A005179(k+3).

Original entry on oeis.org

425, 845, 1265, 1643, 1925, 2525, 2873, 3335, 3395, 3575, 3683, 3971, 4163, 4307, 4343, 4475, 4613, 4667, 4805, 5141, 5285, 5423, 5603, 5945, 6095, 6305, 6683, 6851, 6875, 6893, 6923, 7337, 7661, 7733, 7973, 8075, 8303, 8393, 8453, 8723, 8825, 9191, 9425, 9581, 9821, 9875
Offset: 1

Views

Author

Jianing Song, Dec 05 2021

Keywords

Comments

Numbers k such that both k and k+2 are in A349939.
Numbers k == 5 (mod 6) such that, the smallest number with exactly k divisors is smaller than the smallest number with exactly k-1 or k+1 divisors, and that the smallest number with exactly k+2 divisors is smaller than the smallest number with exactly k+1 or k+3 divisors.

Examples

			The smallest numbers with exactly 424, 425, 426, 427 and 428 divisors are 472877960873902080, 3317760000, 53126622932283508654080, 840479776858391445504 and 1216944576219100225436835077160960 respectively. The smallest number with exactly 425 divisors is smaller than the smallest number with exactly 424 or 426 divisors, the smallest number with exactly 427 divisors is smaller than the smallest number with exactly 426 or 428 divisors, and 425 == 5 (mod 6), so 425 is a term.
		

Crossrefs

Programs

  • PARI
    isA349940(k) = if(k%6==5, my(v=vector(5, n, A005179(k-2+n))); v[2]A005179 for its program