A067468 - OEIS

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A067468

Numbers n such that 7 is the first digit of 7^n.

1, 20, 33, 46, 59, 72, 104, 117, 130, 143, 175, 188, 201, 214, 246, 259, 272, 285, 317, 330, 343, 356, 388, 401, 414, 427, 459, 472, 485, 498, 511, 530, 543, 556, 569, 582, 614, 627, 640, 653, 685, 698, 711, 724, 756, 769, 782, 795, 827, 840, 853, 866, 898

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..53.

MATHEMATICA

Select[Range[1000], IntegerDigits[7^#][[1]]==7&] (* Harvey P. Dale, Aug 04 2023 *)

PROG

(PARI) : for(n=1, 1000, if(floor(7^n/10^(floor(n*log(7)/log(10))))==7, print1(n, ", ")))

CROSSREFS

Cf. A067485.

Sequence in context: A364307 A075230 A165236 * A127906 A108667 A108669

Adjacent sequences: A067465 A067466 A067467 * A067469 A067470 A067471

KEYWORD

nonn,base

AUTHOR

Benoit Cloitre, Feb 22 2002

STATUS

approved