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).

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

1,1

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.

Links

Matthew House, Table of n, a(n) for n = 1..10000

Example

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.

Prog

(PARI) isA349940(k) = if(k%6==5, my(v=vector(5, n, A005179(k-2+n))); v[2]<v[1] && v[2]<v[3] && v[4]<v[3] && v[4]<v[5], 0) \\ See A005179 for its program

Crossrefs

Cf. A005179, A339863, A349939.

Sequence in context: A294714 A294712 A160098 * A203343 A207233 A207226

Adjacent sequences: A349937 A349938 A349939 * A349941 A349942 A349943

Keyword

nonn

Author

Jianing Song, Dec 05 2021

Status

approved