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A298009 a(n) = f(n-1,n)+(n-1)*k, n>=1, where the function f(a,b) gives the number of prime numbers in the range [a*k,b*k[ with k=10^p. For this sequence we use p=2. 0
25, 121, 216, 316, 417, 514, 616, 714, 815, 914, 1016, 1112, 1215, 1311, 1417, 1512, 1615, 1712, 1812, 1913, 2014, 2110, 2215, 2315, 2410, 2511, 2615, 2714, 2812, 2911, 3012, 3110, 3211, 3315, 3411, 3514, 3613, 3712, 3811, 3911, 4015, 4109, 4216, 4309, 4411, 4512, 4612, 4712, 4808, 4915 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Realization of the general term presented in the sequence A298008, for the case of p=2. See detailed comments there.

LINKS

Table of n, a(n) for n=1..50.

FORMULA

a(n) = A038822(n-1) + 100*(n-1); - Michel Marcus, Jan 11 2018

MATHEMATICA

Block[{p = 2, k}, k = 10^p; Array[Apply[Subtract, PrimePi[{k #, k (# - 1)}]] + (# - 1) k &, 50]] (* Michael De Vlieger, Jan 11 2018 *)

PROG

(Python)

# Generates all elements of the sequence smaller than last

last = 1000

p=[2]

c=1

for i in range(3, last+2, 2):

    prime = True

    for j in p:

        if i%j == 0:

            prime=False;

            break;

    if prime == True:

        p.append(i)

        c = c + 1

    ii = int(i/100)*100

    if i-ii == 1:

        if prime == True:

            print '%d, ' % (ii-100+c-1),

            c = 1

        else:

            print '%d, ' % (ii-100+c),

            c = 0

CROSSREFS

Cf. A298008.

Sequence in context: A036057 A083509 A256519 * A213445 A031151 A016970

Adjacent sequences:  A298006 A298007 A298008 * A298010 A298011 A298012

KEYWORD

nonn

AUTHOR

Luis F.B.A. Alexandre, Jan 10 2018

STATUS

approved

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Last modified April 1 05:04 EDT 2020. Contains 333155 sequences. (Running on oeis4.)