id:A143967 - OEIS Search Results

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Numbers containing only digits 3 or 7 in decimal representation.

+0
3

3, 7, 33, 37, 73, 77, 333, 337, 373, 377, 733, 737, 773, 777, 3333, 3337, 3373, 3377, 3733, 3737, 3773, 3777, 7333, 7337, 7373, 7377, 7733, 7737, 7773, 7777, 33333, 33337, 33373, 33377, 33733, 33737, 33773, 33777, 37333, 37337, 37373, 37377 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`See A020463 for primes.`
	FORMULA	`a(n) = f(n+1, 0) with f(n, x) = if n=1 then A004086(x) else f(floor(n/2), 10x + 3 + 4(n mod 2)).`
	CROSSREFS	`A032810.` `Sequence in context: A074699 A115088 A089622 this_sequence A007646 A120566 A057480` `Adjacent sequences: A143964 A143965 A143966 this_sequence A143968 A143969 A143970`
	KEYWORD	`base,nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Sep 06 2008`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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