A169973 - OEIS

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A169973

a(n) = number of ways to write n as a sum of distinct numbers <= n, where the addition is carryless mod 10.

1, 1, 1, 2, 2, 4, 7, 13, 26, 51, 52, 103, 154, 205, 256, 308, 359, 410, 461, 512, 2408, 4814, 20276, 70298, 189440, 427728, 855452, 1583464, 2833460, 5127424, 10197920, 20395832, 42204112, 86360168, 173465856, 345264448, 687194480 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,4`
	COMMENTS	`a(0) = 1 by convention, as in A000009.` `Without the restriction that the parts be distinct, the terms a(n) would be infinite: e.g. 5 = 5 + any number of copies of (1+2+3+4).`
	LINKS	`Table of n, a(n) for n=0..36.` `Index entries for sequences related to carryless arithmetic`
	EXAMPLE	`a(6) = 7: 6 = 6+5+4+1 = 6+5+3+2 = 6+4+3+2+1 = 5+1 = 4+2 = 3+2+1.` `a(7) = 13: 7 = 6+1 = 5+2 = 4+3 = 4+2+1 = 7+6+4 = 7+6+3+1 = 7+5+4+1 = 7+5+3+2 = 7+4+3+2+1 = 6+5+4+2 = 6+5+3+2+1 = 7+6+5+4+3+2.`
	CROSSREFS	`Cf. A000009.` `Sequence in context: A153970 A067953 A109070 * A300353 A049868 A120363` `Adjacent sequences: A169970 A169971 A169972 * A169974 A169975 A169976`
	KEYWORD	`nonn,base`
	AUTHOR	`David Applegate, Marc LeBrun and N. J. A. Sloane, Jul 20 2010`
	EXTENSIONS	`Missing initial a(0)=1 value inserted by Marc LeBrun, Oct 26 2010`
	STATUS	`approved`

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Last modified February 27 11:38 EST 2021. Contains 341656 sequences. (Running on oeis4.)