A381037 Numbers with a digit > 1 in their primorial base expansion that are multiples of the corresponding radix primes of all such digits.

15, 20, 25, 45, 50, 55, 63, 91, 98, 105, 126, 140, 175, 182, 189, 225, 230, 235, 255, 260, 265, 273, 301, 308, 315, 336, 350, 385, 392, 399, 429, 440, 451, 638, 660, 693, 770, 847, 1056, 1089, 1100, 1155, 1232, 1298, 1386, 1485, 1507, 1683, 1705, 1716, 1771, 1892, 2079, 2101, 2145, 2325, 2330, 2335, 2355, 2360, 2365

Offset

1,1

Comments

Numbers k such that A328572(k) > 1 and A007947(A328572(k)) divides k.

Links

Antti Karttunen, Table of n, a(n) for n = 1..12121

Index entries for sequences related to primorial base.

Example

For n=75, A049345(75) = 2211, with two digits > 1. Their corresponding radix primes are 5 and 7, but as 75 is a multiple of only 5 but not of 7, 75 is NOT included in this sequence.
For n = 105, A049345(105) = 3211, with two digits > 1. Their corresponding radix primes are 5 and 7 that both divide 105, therefore 105 is included.
For n = 559469993635709872356669612125495026320977730 [= A276085(855523)], A049345(x) = 200000000001000000000000000000, with digit 2 having a radix prime 113 [= A000040(30)], and as 113 is one of the prime factors of 559469993635709872356669612125495026320977730, that number is included as a term of this sequence. - Added Jan 28 2026, see comments in A380527.

Prog

(PARI) is_A381037 = A381036;

Crossrefs

Subsequence of A381034, thus subsequence of A392611 (which is the intersection A177711 and A381035).

Cf. A003557, A007947, A049345, A276086, A328572, A381036 (characteristic function).

Cf. also A380527.

Sequence in context: A143321 A066860 A381034 * A120159 A163602 A074236

Adjacent sequences: A381034 A381035 A381036 * A381038 A381039 A381040

Keyword

nonn

Author

Antti Karttunen, Feb 17 2025

Status

approved