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A217920 Column 1 of A217916 (when formed into a number triangle). 2
2, 1, 2, 4, 2, 6, 6, 2, 6, 2, 6, 14, 4, 12, 6, 2, 4, 4, 2, 2, 6, 6, 2, 4, 6, 8, 6, 16, 6, 4, 6, 6, 6, 6, 6, 6, 14, 6, 6, 14, 10, 10, 8, 4, 12, 20, 8, 12, 6, 10, 2, 6, 14, 2, 14, 18, 6, 2, 6, 12, 4, 28, 6, 20, 6, 6, 6, 4, 16, 2, 2, 6, 4, 12, 6, 6, 6, 6, 8, 4, 6, 8, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The number 2 appears in A217916 only in column 1.

The positions of 2 are given by A217919.

LINKS

Paul D. Hanna, Table of n, a(n) for n = 1..287

FORMULA

a(n) = prime(n*(n-1)/2 + 1) - prime(n*(n-1)/2) for n>1 with a(1)=2.

CROSSREFS

Cf. A217916, A217918, A217919.

Sequence in context: A060547 A079878 A324469 * A137406 A181293 A262876

Adjacent sequences:  A217917 A217918 A217919 * A217921 A217922 A217923

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Mar 04 2013

STATUS

approved

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Last modified July 22 14:31 EDT 2019. Contains 325222 sequences. (Running on oeis4.)