A346141 Numbers k whose number of divisors equals the number of divisors in each of R(k), k+R(k), R(k+R(k)), abs(k-R(k)), and R(abs(k-R(k))), where R(m) is the digit reversal of m and where the reversals of m do not equal m.

117858, 129138, 137976, 138222, 194838, 201569, 222831, 281256, 302844, 439415, 448203, 454016, 500638, 514934, 516378, 526486, 533938, 552926, 560766, 562936, 595016, 607499, 607597, 610454, 610595, 629255, 639265, 652182, 654018, 659358, 667065, 679731, 684625, 795706, 810456, 813179

Offset

1,1

Comments

There are 324 terms below 50 million. In that range the number of divisors of the terms is 8,12,16,24,32 or 48. The first term with 8 divisors is 129138, the first with 12 is 302844, the first with 16 is 117858, the first with 24 is 138222, the first with 32 is 26739192, and the first with 48 is 19245366.

Links

Table of n, a(n) for n=1..36.

Example

117858 is a term as the number of divisors of 117858 = tau(117858) = 16, and this equals tau(R(117858)) = tau(858711) = 16, tau(117858+R(117858)) = tau(976569) = 16, tau(R(117858+R(117858))) = tau(965679) = 16, tau(abs(117858-R(117858))) = tau(740853) = 16, and tau(R(abs(117858-R(117858)))) = tau(358047) = 16.

Crossrefs

Cf. A000005, A004086, A346113, A056964, A056965.

Subsequence of A062895.

Sequence in context: A251882 A237208 A089524 * A235837 A235832 A111112

Adjacent sequences: A346138 A346139 A346140 * A346142 A346143 A346144

Keyword

nonn,base

Author

Scott R. Shannon, Jul 05 2021

Status

approved