id:A137728 - OEIS Search Results

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Second digit from the end of product of first n primes.

+0
2

0, 0, 3, 1, 1, 3, 1, 9, 7, 3, 3, 1, 1, 3, 1, 3, 7, 7, 9, 9, 7, 3, 9, 1, 7, 7, 1, 7, 3, 9, 3, 3, 1, 9, 1, 1, 7, 1, 7, 1, 9, 9, 9, 7, 9, 1, 1, 3, 1, 9, 7, 3, 3, 3, 1, 3, 7, 7, 9, 9, 7, 1, 7, 7, 1, 7, 7, 9, 3, 7, 1, 9, 3, 9, 1, 3, 7, 9, 9, 1, 9, 9, 9, 7, 3, 9, 1, 7, 7, 1, 7, 3, 1, 1, 9, 7, 3, 3, 9, 9, 3, 1, 3, 7, 7 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`a(1) = a(2) = 0 because Prime(1) = 2 and Prime(1)*Prime(2) = 6 are one-digit numbers.`
	FORMULA	`a(n) = Mod[ p#/10, 10 ] for n>2 and a(1) = a(2) = 0.`
	MATHEMATICA	`a(1) = a(2) = 0, for n>2 Table[ Mod[ Product[ Prime[n], {n, 1, k} ], 100 ]/10, {k, 3, 1000} ]`
	CROSSREFS	`Cf. A007652 = Final digit of prime(n). Cf. A110923 = Final two digits of prime(n) (with leading zero omitted). Cf. A137727 = Final digit of prime(n)*prime(n+1). Cf. A002110 = Primorial numbers (first definition): product of first n primes. Sometimes written p#.` `Sequence in context: A131327 A122506 A010274 this_sequence A054398 A093415 A106749` `Adjacent sequences: A137725 A137726 A137727 this_sequence A137729 A137730 A137731`
	KEYWORD	`nonn,base`
	AUTHOR	`Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 08 2008`

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.

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