A259199 Divisorial primes ending with digit 1.

101, 34188010001, 254116810001, 283982410001, 2601446410001, 13308633610001, 39691260010001, 52361143210001, 58873394410001, 88828740010001, 155274028810001, 451651754410001, 1004693469610001, 1236570192010001, 2100654722410001, 2886794695210001, 3353811326410001

Offset

1,1

Comments

A divisorial prime is a prime p of the form p = 1 + Product_{d|k} d for some k (see A007955 and A258455).

Sequence lists divisorial primes p of the form h*10^m + 1 (h, m are positive integers).

Sequence of numbers sqrt(a(n) - 1): 10, 184900, 504100, 532900, 1612900, 3648100, 6300100, 7236100, 7672900, ...

Sequence of numbers k such that 1 + Product_{d|k} d is a divisorial prime ending with digit 1: 10, 430, 510, 680, 710, 730, ...

Intersection of A030430 and A258455. - Michel Marcus, Sep 14 2015

Links

Chai Wah Wu, Table of n, a(n) for n = 1..145

Formula

Subsequence of A258455.

Example

Prime 34188010001 is in sequence because 34188010000 is the product of divisors of 430.
1 + the product of divisors of 3000 = 43046721000000000000000000000000000000000000000000000001 is also a term of this sequence.

Prog

(Magma) Set(Sort([&*(Divisors(n))+1: n in [1..10000] | IsSquare(&*(Divisors(n))) and IsPrime(&*(Divisors(n))+1) and (&*(Divisors(n))) mod 10 eq 0]))

Crossrefs

Cf. A007955, A030430, A174895, A258455, A258896, A258897.

Sequence in context: A292686 A138720 A262627 * A006064 A230304 A015164

Adjacent sequences: A259196 A259197 A259198 * A259200 A259201 A259202

Keyword

nonn,base

Author

Jaroslav Krizek, Jun 20 2015

Status

approved