1,2

List of prime-powers where A057820 increases.

The entry K=a(k) is the start of the smallest chain of m=A121492(k) consecutive numbers such that lcm(1,2,...,K)=lcm(1,2,...,K,K+1)=lcm(1,2,...,K,K+1,K+2)=...=lcm(1,2,...,K,...,K+m-1). See A121493. - Lekraj Beedassy (blekraj(AT)yahoo.com), Aug 03 2006

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

J. P. Gram, Undersoegelser angaaende maengden af primtal under en given graense, Det Kongelige Danskevidenskabernes Selskabs Skrifter, series 6, vol. 2 (1884), 183-288; see p. 255.

Donovan Johnson, Table of n, a(n) for n=1..79 [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 14 2008]

Index entries for primes, gaps between

Contribution from Michael Porter (michael_b_porter(AT)yahoo.com), Oct 31 2009: (Start)

(PARI) /* calculates smaller terms - see Donovan Johnson link for larger terms */

isA000961(n) = (omega(n) == 1 | n == 1)

d_max=0; n_prev=1; for(n=2, 1e6, if(isA000961(n), d=n-n_prev; if(d>d_max, print(n_prev); d_max=d); n_prev=n)) (End)

Cf. A000961 (prime-powers), A057820 (gaps).

Sequence in context: A129919 A045454 A166575 this_sequence A082093 A045455 A160031

Adjacent sequences: A002537 A002538 A002539 this_sequence A002541 A002542 A002543

nonn,nice,new

N. J. A. Sloane (njas(AT)research.att.com).

Second term corrected by Donovan Johnson, Nov 13 2008 (cf. A094158).

a(28)-a(79) and b-file from Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 14 2008