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Table of n, a(n) for n=1..56.
a(1)=2+0=2, a(2)=4+1=5, a(3)=6+3=9, a(4)=12+5=17.
Cf. A167706, A167707.
Sequence in context: A036711 A080740 A123324 * A023603 A062492 A268346
Adjacent sequences: A167884 A167885 A167886 * A167888 A167889 A167890
Juri-Stepan Gerasimov, Nov 14 2009
All terms > 110 corrected by R. J. Mathar, May 30 2010