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A114321 Difference between first odd semiprime > 11^n and 11^n. 0
8, 4, 2, 2, 6, 14, 4, 6, 6, 6, 4, 6, 32, 14, 10, 2, 12, 2, 2, 12, 36, 6, 28, 6, 12, 32, 8, 12, 28, 24, 48 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

A098147 is difference between first odd semiprime > 10^n and 10^n.

LINKS

Table of n, a(n) for n=0..30.

FORMULA

a(n) = minimum integer k such that 11^n + k is an element of A046315. a(n) = minimum integer k such that A001020(n) + k is an element of A046315.

EXAMPLE

a(0) = 8 because 11^0 + 8 = 9 = 3^2 is an odd semiprime.

a(1) = 4 because 11^1 + 4 = 15 = 3 * 5 is an odd semiprime.

a(2) = 2 because 11^2 + 2 = 123 = 3 * 41.

a(3) = 2 because 11^3 + 2 = 1333 = 31 * 43 (brilliant).

a(4) = 6 because 11^4 + 6 = 14647 = 97 * 151.

a(5) = 14 because 11^5 + 14 = 161065 = 5 * 32213.

a(6) = 4 because 11^6 + 4 = 1771565 = 5 * 354313.

a(7) = 6 because 11^7 + 6 = 19487177 = 41 * 475297.

a(8) = 6 because 11^8 + 6 = 214358887 = 317 * 676211.

a(9) = 6 because 11^9 + 6 = 2357947697 = 7 * 336849671.

a(10) = 4 because 11^10 + 4 = 25937424605 = 5 * 5187484921.

a(30) = 48 because 11^30 + 48 = 17449402268886407318558803753849 = 7 * 2492771752698058188365543393407.

CROSSREFS

Cf. A001020, A001358, A098147.

Sequence in context: A131606 A033328 A097529 * A154434 A222301 A198353

Adjacent sequences:  A114318 A114319 A114320 * A114322 A114323 A114324

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Feb 05 2006

STATUS

approved

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Last modified November 13 15:41 EST 2019. Contains 329106 sequences. (Running on oeis4.)