

A169973


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


0



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
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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



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



KEYWORD

nonn,base


AUTHOR



EXTENSIONS

Missing initial a(0)=1 value inserted by Marc LeBrun, Oct 26 2010


STATUS

approved



