A163631 - OEIS

A163631

Partial sums of the odd nonprimes, A014076.

1, 10, 25, 46, 71, 98, 131, 166, 205, 250, 299, 350, 405, 462, 525, 590, 659, 734, 811, 892, 977, 1064, 1155, 1248, 1343, 1442, 1547, 1658, 1773, 1890, 2009, 2130, 2253, 2378, 2507, 2640, 2775, 2916, 3059, 3204, 3351, 3504, 3659, 3818, 3979, 4144, 4313

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

All entries besides the first are of the form 2+(k+1)^2-A007504(j), e.g., 10=2+25-17, 25=2+64-41, where the square is the sum of all odd numbers up to 1+2*k, and the 2 and A007504 represent the partial sum over the primes.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..5000

FORMULA

a(n) = Sum_{x= 1st odd nonprime..n-th odd nonprime}x.

MATHEMATICA

upto=200; Accumulate[Complement[Range[1, upto, 2], Prime[Range[2, PrimePi[upto]]]]] (* Harvey P. Dale, Mar 19 2011 *)

PROG

(PARI) lista(nn) = {my(s = 0); forstep (n=1, nn, 2, if (!isprime(n), s+= n; print1(s, ", ")); ); } \\ Michel Marcus, Aug 01 2017

CROSSREFS

Cf. A014076.

Sequence in context: A269457 A043123 A043903 * A100536 A024838 A020179

Adjacent sequences: A163628 A163629 A163630 * A163632 A163633 A163634

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Aug 02 2009, Oct 10 2009

EXTENSIONS

150 replaced with 250 by R. J. Mathar, Aug 06 2009

STATUS

approved

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