A073850 - OEIS

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A073850

Cumulative sum of initial digits of (n base 4).

0, 1, 3, 6, 7, 8, 9, 10, 12, 14, 16, 18, 21, 24, 27, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 127, 128, 129, 130 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	FORMULA	`a(n) = SUM[from i = 0 to n] Initial-Digit(A007090(n)). a(n) = SUM{from i = 0 to n} first-digit{(i base 4)} where (i base 4) = A007090(i); A007090(0)=0, A007090(i)=10*A007090(i/4) if i==0 (mod 4), A007090(i)= A007090(i-1)+1 otherwise.`
	EXAMPLE	`n Base 4 Init Cum Sum` `0 0 0 0` `1 1 1 1` `2 2 2 3` `3 3 3 6` `4 10 1 7` `5 11 1 8`
	CROSSREFS	`Cf. A007090, A109453.` `Sequence in context: A112267 A068985 A081391 * A048748 A030781 A073417` `Adjacent sequences: A073847 A073848 A073849 * A073851 A073852 A073853`
	KEYWORD	`base,easy,nonn`
	AUTHOR	`Jonathan Vos Post (jvospost3(AT)gmail.com), Aug 28 2005`

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Last modified February 15 04:23 EST 2012. Contains 205694 sequences.