A161569 - OEIS

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A161569

Sum of first n nonprimes minus their indices.

0

0, 2, 5, 9, 13, 17, 22, 28, 34, 40, 47, 55, 63, 71, 80, 89, 98, 107, 116, 126, 137, 148, 159, 170, 181, 193, 205, 217, 230, 244, 258, 272, 287, 302, 317, 332, 347, 363, 379, 395, 411, 427, 444, 462, 480, 498, 516, 534, 553, 572, 591, 611, 632, 653, 674, 695, 716

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OFFSET

1,2

COMMENTS

The sum of first n nonprimes is in A051349.

Partial sums of A073425. - Jaroslav Krizek, Jun 27 2009

LINKS

Table of n, a(n) for n=1..57.

FORMULA

a(n) = A051349(n)-n*(n+1)/2.

a(n) = a(n-1)+A018252(n)-n, a(1) = 0. - Klaus Brockhaus, Dec 16 2010

EXAMPLE

a(1) = 1-1 = 0; a(2) = 0+4-2 = 2, a(3) = 2+6-3 = 5; a(4) = 5+8-4 = 9.

CROSSREFS

Cf. A073425, A051349, A018252, A112997.

Sequence in context: A050877 A063203 A130244 * A263086 A353036 A182814

Adjacent sequences: A161566 A161567 A161568 * A161570 A161571 A161572

KEYWORD

nonn,easy

AUTHOR

Juri-Stepan Gerasimov, Jun 14 2009

EXTENSIONS

a(54)-a(57) from Stefano Spezia, May 26 2025

STATUS

approved