OFFSET
1,1
COMMENTS
The differences are always odd since the parity of A101306 and n are always opposite.
Positions where a(n)=2k-1 for k>0; 10, 1, 2, 5, 6, 20, 21, 62, 64, 65, 67, 198, 761, 765, 764, 800, ... - Robert G. Wilson v, Jun 06 2012
FORMULA
a(n) = 5*n - Sum_{i=1..n} Prime(i) (mod 10).
MATHEMATICA
f[n_] := 5n - Sum[ Mod[ Prime@ k, 10], {k, n}]; Array[f, 80]
Rest@ FoldList[# + 5 - Mod[Prime@ #2, 10] &, 0, Range@ 80]
CROSSREFS
KEYWORD
base,easy,sign
AUTHOR
Robert G. Wilson v, Jan 17 2011
STATUS
approved