A374295 - OEIS

A374295

a(n) is the smallest positive integer k such that A096936(k) = n.

1, 7, 4, 91, 2401, 28, 117649, 1729, 196, 31213, 282475249, 364, 13841287201, 1529437, 9604, 53599, 33232930569601, 2548, 1628413597910449, 593047, 470596, 3672178237, 3909821048582988049, 6916, 68574961, 179936733613, 33124, 29059303, 459986536544739960976801, 124852

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OFFSET

1,2

COMMENTS

a(n) is the smallest positive integer k such that A033716(k) = 2*n,

LINKS

Table of n, a(n) for n=1..30.

FORMULA

If p is prime, a(p) = 7^(p-1).

a(n) is divisible by 7 for n > 3.

EXAMPLE

n | a(n)

------------+-------------------------------------

2 | 7.

3 = 3*1 | 4.

4 | 91 = 7 * 13.

5 | 2401 = 7^4.

6 = 3*2 | 28 = 4 * 7.

7 | 117649 = 7^6.

8 | 1729 = 7 * 13 * 19.

9 = 3*3 | 196 = 4 * 7^2.

10 | 31213 = 7^4 * 13.

11 | 282475249 = 7^10.

12 = 3*4 | 364 = 4 * 7 * 13.

13 | 13841287201 = 7^12.

14 | 1529437 = 7^6 * 13.

15 = 3*5 | 9604 = 4 * 7^4.

16 | 53599 = 7 * 13 * 19 * 31.

17 | 7^16.

18 = 3*6 | 2548 = 4 * 7^2 * 13.

19 | 7^18.

20 | 593047 = 7^4 * 13 * 19.

21 = 3*7 | 470596 = 4 * 7^6.

22 | 3672178237 = 7^10 * 13.

23 | 7^22.

24 = 3*8 | 6916 = 4 * 7 * 13 * 19.

25 | 68574961 = 7^4 * 13^4.

26 | 179936733613 = 7^12 * 13.

27 = 3*9 | 33124 = 4 * 7^2 * 13^2.

28 | 29059303 = 7^6 * 13 * 19.

29 | 7^28.

30 = 3*10 | 124852 = 4 * 7^4 * 13.

CROSSREFS

Cf. A033716, A096936, A343771.

Sequence in context: A038270 A241359 A239602 * A100976 A152627 A277067

Adjacent sequences: A374292 A374293 A374294 * A374296 A374297 A374298

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Jul 02 2024

STATUS

approved