id:A137589 - OEIS Search Results

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a(n) = first digit of p(n) concatenated with final digit of p(n); where p(n) = n-th prime number.

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2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 11, 13, 17, 19, 13, 17, 11, 17, 19, 19, 11, 17, 13, 17, 13, 19, 11, 11, 13, 17, 19, 21, 23, 27, 29, 23, 29, 21, 21, 27, 23, 29, 21, 27, 21, 23, 23, 37, 31, 33, 37, 31, 37, 37, 39, 33 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`The plot of this sequence shows number of primes on the x-axis and the split of primes into 9 groups according to their first digit on the y-axis. The plot of a(n+1)/a(n) oscillates around 1 with decreasing amplitude. Log-periodic growth is seen on the plot of partial sums : b(n)= sum_(i=1..n)(a(i)).`
	FORMULA	`a(n) = first digit of p(n) concatenated with final digit of p(n); p(n) n-th prime number.`
	CROSSREFS	`Cf. A000040, A007652, A010879.` `Sequence in context: A118848 A094742 A110923 this_sequence A052424 A055398 A070159` `Adjacent sequences: A137586 A137587 A137588 this_sequence A137590 A137591 A137592`
	KEYWORD	`easy,base,nonn`
	AUTHOR	`Ctibor O. Zizka (ctibor.zizka(AT)seznam.cz), Apr 26 2008`

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

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