A161625 - OEIS

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A161625

Sum of all numbers from 1 up to the final digit of prime(n).

3, 6, 15, 28, 1, 6, 28, 45, 6, 45, 1, 28, 1, 6, 28, 6, 45, 1, 28, 1, 6, 45, 6, 45, 28, 1, 6, 28, 45, 6, 28, 1, 28, 45, 45, 1, 28, 6, 28, 6, 45, 1, 1, 6, 28, 45, 1, 6, 28, 45, 6, 45, 1, 1, 28, 6, 45, 1, 28, 1, 6, 6, 28, 1, 6, 28, 1, 28, 28, 45, 6, 45, 28, 6, 45, 6, 45, 28, 1, 45

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..80.

FORMULA

a(n)= A000217(A007652(n)). - R. J. Mathar, Jun 16 2009

EXAMPLE

a(1)=3=1+2. a(2)=6=1+2+3. a(3)=15=1+2+3+4+5. a(4)=28=1+2+3+4+5+6+7. a(5)=1=1. a(6)=3=1+2.

MAPLE

A007652 := proc(n) ithprime(n) mod 10; end: A000217 := proc(n) n*(n+1)/2 ; end:

A161625 := proc(n) A000217(A007652(n)) ; end: seq(A161625(n), n=1..80) ; # R. J. Mathar, Jun 16 2009